Trackers

Trackers print debugging information to the log file. They can be enabled with \enabletrackers:

\enabletrackers[tracker,tracker,...]

This list was originally made by grepping for trackers.register in the source code; it can also be produced from the command line with

context --showtrackers

Details here about Trackers/typesetters.suspects and Trackers/visualizers.justification.

Tracker	Description	Files
afm.features		font-afm.lua
afm.indexing		font-afm.lua
afm.loading		font-afm.lua
alignments.showstates
attachments.anchors
attributes.tags
attributes.values
backend.cleanup
backend.details		lpdf-ini.lua
backend.fields		lpdf-fld.lua
backend.finalizers		lpdf-ini.lua
backend.format		lpdf-fmt.lua
backend.fonts
backend.fonts.details
backend.format
backend.info		lpdf-xmp.lua
backend.initializers	(gone?)	back-ini.lua
backend.javascript		java-ini.lua
backend.objects		lpdf-ini.lua
backend.primitives
backend.resources		lpdf-ini.lua
backend.swf	(gone?)	lpdf-swf.lua
backend.variables		lpdf-fmt.lua
backend.whatsits
backend.xmp		lpdf-xmp.lua
backgrounds.alignments
backgrounds.shapes
backgrounds.shapes.free
backgrounds.shapes.ranges
btxrendering
buffers.grab		buff-ini.lua
buffers.parallel		buff-par.lua
buffers.run		buff-ini.lua
buffers.visualize		buff-ini.lua, buff-ver.lua
builders.collect_vspacing	(gone?)	spac-ver.lua
builders.hpack.collect
builders.hpack.overflow	mark under-/overfull hboxes
builders.hpack.quality
builders.page
builders.page.show
builders.page_vspacing	(gone?)	spac-ver.lua
builders.paragraphs.adjusting
builders.paragraphs.basic
builders.paragraphs.expansion
builders.paragraphs.expansion.both
builders.paragraphs.expansion.verbose
builders.paragraphs.lastlinefit
builders.paragraphs.protruding
builders.paragraphs.solutions. ... ... splitters.colors		node-spl.lua
builders.paragraphs.solutions. ... ... splitters.optimizer		node-spl.lua
builders.paragraphs.solutions. ... ... splitters.splitter		node-spl.lua
builders.post
builders.vbox
builders.vbox_vspacing	(gone?)	spac-ver.lua
builders.vpack.collect
builders.vpack.quality
builders.vpacking	(gone?)	spac-ver.lua
builders.vsnapping	(gone?)	spac-ver.lua
builders.vspacing	(gone?)	spac-ver.lua
characters.defining		char-ini.lua
chemistry.boundingbox
chemistry.boxes
chemistry.metapost
chemistry.molecules		chem-ini.lua
chemistry.structure		chem-str.lua
chemistry.textstack		chem-str.lua
colors.define		colo-ini.lua
colors.pgf
columnsets.cells
columnsets.details
columnsets.trace
comments.anchors
context.define		cldf-int.lua
context.files		cldf-ini.lua
context.trace		cldf-ini.lua
converters.hebrew
delimited.language
discretionaries
export.trace		back-exp.lua
export.trace.details		back-exp.lua
export.trace.math		back-exp.lua
export.trace.spacing		back-exp.lua
figures.comments
figures.conversion		grph-wnd.lua
figures.fields
figures.inclusion		grph-u3d.lua
figures.links		lpdf-epa.lua
figures.merging
figures.outlines
floats.anchoring
floats.caching
floats.collecting
floats.freeregion
fonts.addcharacters
fonts.automode		font-ctx.lua
fonts.cff.charstrings
fonts.collecting		font-col.lua
fonts.combining	(gone?)	font-fbk.lua
fonts.combining.all	(gone?)	font-fbk.lua
fonts.composing.define		font-fbk.lua
fonts.composing.visualize		font-fbk.lua
fonts.defining		font-afm.lua, font-con.lua, font-ctx.lua, font-enh.lua, font-log.lua, font-lua.lua, font-otf.lua, font-tfm.lua
fonts.designsize		font-ctx.lua
fonts.effect
fonts.expansion		font-ext.lua
fonts.features		font-ctx.lua
fonts.goodies		font-gds.lua, node-spl.lua
fonts.goodies.extensions		font-gds.lua, node-spl.lua
fonts.injections
fonts.injections.cursive
fonts.injections.marks
fonts.injections.spaces
fonts.loading		font-def.lua, font-map.lua
fonts.mapfiles		font-ctx.lua
fonts.mapping		font-map.lua
fonts.merge
fonts.missing		font-chk.lua
fonts.names		font-syn.lua
fonts.otf.loader.memory
fonts.protrusion		font-ext.lua
fonts.rejections
fonts.reorderlookups
fonts.result.show
fonts.sanitizers
fonts.scaling		font-con.lua
fonts.specifications		font-syn.lua
fonts.stripping		typo-rep.lua
fonts.treatments
fonts.unicoding
fonts.usage		font-ctx.lua
fonts.warnings		font-syn.lua
formulas.framed
framed.math
graphics.backend
graphics.bases		grph-inc.lua
graphics.conversion		grph-inc.lua
graphics.fixes	(mentioned in pdfmerge manual without explanation)
graphics.floats	(gone?)	page-flt.lua
graphics.fonts	“reports what is done with fonts” (pdfmerge manual)
graphics.fonts.details
graphics.inclusion		grph-inc.lua
graphics.inheritance
graphics.locating		grph-inc.lua
graphics.programs		grph-inc.lua
graphics.operators
graphics.pdf
graphics.programs
graphics.runfile		grph-fil.lua
graphics.usage
hyphenation.applied
hyphenation.applied.console	show hyphenation in log
hyphenation.applied.visualize	show hyphens in red and possible breaks in ligatures in blue
hyphenator.steps
hyphenator.visualize
hyphenator.urls
interfaces.namespaces		mult-aux.lua
job.datasets		core-dat.lua
job.pagestates		core-dat.lua
languages.applied
languages.goodies
languages.labels		lang-lab.lua
languages.patterns		lang-ini.lua
languages.replacements
languages.replacements.details
languages.transliteration
languages.url
layout.vz	vertical stretching
linecorrection.boxes
lines.numbers		page-lin.lua
lines.numbers.show
lmx.variables
localanchor
lxml.access		lxml-tex.lua
lxml.comments		lxml-tex.lua
lxml.inclusions		lxml-tex.lua
lxml.loading		lxml-tex.lua
lxml.manipulations		lxml-aux.lua
lxml.manipulations		lxml-tex.lua
lxml.selectors		lxml-tex.lua
lxml.setups		lxml-tex.lua
marks.detail	(gone?)	strc-mar.lua
marks.get	(gone?)	strc-mar.lua
marks.set	(gone?)	strc-mar.lua
math.align
math.alternates
math.analyzing		math-noa.lua
math.autohang
math.checkitalics
math.classes
math.collapsing		math-noa.lua
math.collecting
math.defining		math-act.lua, math-ini.lua
math.dictionaries
math.dictionaries.details
math.fallbacks
math.families		math-noa.lua
math.fencenesting
math.fences
math.goodies		math-noa.lua
math.greek		math-map.lua
math.intervals
math.italics	(gone?)	math-noa.lua
math.kernpairs
math.makeup
math.matrices.hl
math.normalizing		math-noa.lua
math.numberdistance
math.numbering
math.openedup
math.processing		math-noa.lua
math.remapping		math-noa.lua
math.showmargins
math.showmargins.less
math.showtree
math.snapping
math.stackers.texts
math.suspicious
math.textblobs
math.timings		math-vfu.lua
math.toysymbol
math.tweaks
math.unstack
math.variants		math-noa.lua
math.virtual		math-ext.lua, math-vfu.lua
memory.checking		luat-cbk.lua
metapost.graphics		mlib-run.lua
metapost.blobs
metapost.btexetex
metapost.forcestroke
metapost.graphics
metapost.instance
metapost.lua
metapost.nodes
metapost.properties
metapost.runs		mlib-pps.lua
metapost.script
metapost.scripts		mlib-pps.lua
metapost.showlog
metapost.svg
metapost.svg.colors
metapost.svg.fonts
metapost.svg.path
metapost.svg.result
metapost.svg.text
metapost.terminal
metapost.textexts		mlib-pps.lua
metapost.tracingall
metapost.variables
mixedcolumns.boxes
mixedcolumns.details
mixedcolumns.trace
modules.asciimath.mapping	(gone?)	x-asciimath.lua
modules.database.flush	(gone?)	m-database.lua
modules.loading		file-mod.lua
nodes.areas
nodes.backend	(gone?)	node-ref.lua
nodes.boxes
nodes.callbacks		node-pro.lua
nodes.characters		node-fnt.lua
nodes.destinations		node-ref.lua
nodes.destinations.show		node-ref.lua
nodes.directions
nodes.fontrun		node-fnt.lua
nodes.frequencies
nodes.injections	(gone?)	node-inj.lua
nodes.migrations		node-mig.lua
nodes.references		node-ref.lua
nodes.references.show		node-ref.lua
nodes.rules		node-rul.lua
nodes.shadowing
nodes.shifting		node-rul.lua
nodes.stripping		typo-rep.lua
nodes.variants
objects
otf.actions		font-otn.lua
otf.alternatives		font-otb.lua, font-otn.lua
otf.analyzing		font-ota.lua
otf.applied		font-otd.lua, font-otn.lua
otf.baseinit		font-otb.lua
otf.bugs		font-otn.lua
otf.chains		font-otn.lua
otf.cleanups		font-otn.lua
otf.cmap		font-otn.lua
otf.cmap.details		font-otn.lua
otf.compruns		font-otn.lua
otf.contexts		font-otn.lua
otf.cursive		font-otn.lua
otf.details		font-otn.lua
otf.directions	(gone?)	font-otn.lua
otf.dynamics		font-otd.lua, font-otf.lua
otf.features		font-otf.lua
otf.injections		font-otn.lua
otf.kernruns
otf.kerns		font-otb.lua, font-otn.lua
otf.ligatures		font-otb.lua, font-otn.lua
otf.loading		font-cid.lua, font-otc.lua, font-otf.lua, font-otp.lua
otf.lookups	(gone?)	font-otn.lua
otf.marks		font-otn.lua
otf.markwidth		font-otf.lua
otf.multiples		font-otb.lua, font-otn.lua
otf.optimizations		font-otn.lua
otf.packing		font-otn.lua
otf.plugins		font-otn.lua
otf.positions		font-otn.lua
otf.preparing		font-otb.lua, font-otn.lua
otf.private	(gone?)	font-otf.lua
otf.replacements	(gone?)	font-otn.lua
otf.sample		font-otn.lua
otf.sample.silent		font-otn.lua
otf.sequences	(gone?)	font-otf.lua
otf.singles	(gone?)	font-otb.lua, font-otn.lua
otf.skips		font-otn.lua
otf.steps		font-otn.lua
otf.substitutions		font-otn.lua
otf.testruns		font-otn.lua
otf.unicodes		font-otn.lua
otf.verbose_chain	(gone?)	font-otn.lua
otr.forcestrutdepth
otr.insertheights
pagebuilder.injections
pagebuilder.insert
pages.loners
pages.mark
pages.timing		trac-log.lua
paragraphs.anchors
paragraphs.passes
paragraphs.passes.callbacks
paragraphs.tweaks
parbuilders.keeptogether		typo-pag.lua
physics.units		phys-dim.lua
potrace.results
profiling.lines.details
profiling.lines.show
profiling.show
profiling.trace
publications
publications.authorhash
publications.bibtex	(gone?)	bibl-tra.lua
publications.bibxml	(gone?)	bibl-bib.lua
publications.cite
publications.cite.missing
publications.cite.references
publications.details
publications.duplicates
publications.match
publications.setups
publications.sorters
publications.strings
publications.suffixes
publications.textblobs
references.bookmarks		lpdf-ano.lua, strc-bkm.lua
references.destinations		lpdf-ano.lua
references.references		lpdf-ano.lua
regimes.translating		regi-ini.lua
resolvers.cache		data-con.lua, data-tmp.lua
resolvers.containers		data-con.lua
resolvers.details		data-ini.lua, data-res.lua
resolvers.expansions		data-exp.lua, data-ini.lua, data-res.lua
resolvers.globbing
resolvers.hash
resolvers.lib
resolvers.lib.silent
resolvers.libraries
resolvers.locating		data-aux.lua, data-exp.lua, data-fil.lua, data-ini.lua, data-lua.lua, data-met.lua, data-res.lua, data-tex.lua, data-tmp.lua, data-tre.lua, data-use.lua, data-vir.lua, data-zip.lua, luat-env.lua
resolvers.methods		data-met.lua
resolvers.paths
resolvers.readfile		file-lib.lua, file-res.lua
resolvers.readfile.details		file-lib.lua, file-res.lua
resolvers.schemes		data-sch.lua
resolvers.storage		data-con.lua
resolvers.virtual		data-vir.lua
rules.mp
sandbox
sandbox.tracecalls
sandbox.tracefiles
scripts.analyzing		scrp-ini.lua
scripts.autofeature		scrp-ini.lua
scripts.details		scrp-ini.lua
scripts.injections		scrp-ini.lua
scripts.splitting		scrp-ini.lua
scripts.splitting.details		scrp-ini.lua
selectfont.alternatives
selectfont.features
selectfont.files
selectfont.goodies
selectfont.register
selectfont.typescripts
sequencers.details
sequencers.used
sorters.methods		sort-ini.lua
sorters.orders		sort-ini.lua
sorters.replacements		sort-ini.lua
sorters.tests		sort-ini.lua
stacker.resolve
streams.collecting		page-str.lua
streams.flushing		page-str.lua
structures.counters		strc-num.lua
structures.detail		strc-doc.lua
structures.lists		strc-lst.lua
structures.notes		strc-not.lua
structures.notes.references		strc-not.lua
structures.pages		strc-pag.lua
structures.referencing		strc-ref.lua
structures.referencing.analyzing		strc-ref.lua
structures.referencing.empty		strc-ref.lua
structures.referencing.external		strc-ref.lua
structures.referencing.identifying		strc-ref.lua
structures.referencing.importing		strc-ref.lua
structures.referencing.show		strc-ref.lua
structures.registers		strc-reg.lua
structures.sectioning		strc-doc.lua
structures.showused		strc-doc.lua
structures.sidefloats.pageflush		strc-doc.lua
structures.tags		lpdf-tag.lua, strc-tag.lua
structures.tags.blobs		lpdf-tag.lua, strc-tag.lua
structures.tags.info		lpdf-tag.lua, strc-tag.lua
structures.tags.internals		lpdf-tag.lua, strc-tag.lua
structures.tags.math		lpdf-tag.lua, strc-tag.lua
structures.tags.math.keeplast		lpdf-tag.lua, strc-tag.lua
structures.tags.math.times		lpdf-tag.lua, strc-tag.lua
structures.tags.showtree		lpdf-tag.lua, strc-tag.lua
structures.tags.suspects		lpdf-tag.lua, strc-tag.lua
svg.text
synchronize
system.callbacks		luat-cbk.lua
system.directives		trac-set.lua
system.dump		luat-run.lua
system.experiments		trac-set.lua
system.jobfiles		file-job.lua
system.jobstatus		file-job.lua
system.namespaces	(gone?)	trac-pro.lua
system.prepfiles		core-ctx.lua
system.randomizer
system.randomizer.details
system.showcodes	(gone?)	node-ini.lua
system.structure
system.synctex.visualize
system.synctex.xml
system.tempfiles		luat-run.lua
system.texstatus
system.usage
tables.natural.widths
tables.tabulate.breaks
tasks.creation		node-tsk.lua
templates.trace
tfm.features		font-tfm.lua
tfm.loading		font-tfm.lua
tokens.compile
typesetters.breakpoints		typo-brk.lua
typesetters.casing		typo-cap.lua
typesetters.characteralign
typesetters.characters		spac-chr.lua
typesetters.cleaners		typo-cln.lua
typesetters.cleaners.autocase		typo-cln.lua
typesetters.digits		typo-dig.lua
typesetters.directions		typo-dir.lua
typesetters.directions.details		typo-dir.lua
typesetters.directions.list		typo-dir.lua
typesetters.directions.math		typo-dir.lua
typesetters.directions.text		typo-dir.lua
typesetters.firstlines
typesetters.initials
typesetters.invisibles
typesetters.italics		typo-itc.lua
typesetters.kerns.ligatures
typesetters.kerns.ligatures.details
typesetters.margindata		spac-ali.lua, typo-mar.lua
typesetters.margindata.group		spac-ali.lua, typo-mar.lua
typesetters.margindata.stack		typo-mar.lua
typesetters.nbsp
typesetters.paragraphs	(gone?)	typo-par.lua
typesetters.paragraphs.dropper	(gone?)	typo-par.lua
typesetters.periodkerns
typesetters.processors		strc-ini.lua, typo-prc.lua
typesetters.rubies
typesetters.spacing		typo-spa.lua
typesetters.suspects	mark potential spacing/interpunction errors	typo-sus.mkxl, typo-sus.lmt
typesetters.tighten
typesetters.twindemerits
typesetters.wrappers
visualizers.all	lots of colorful markers
visualizers.boundary
visualizers.boxes
visualizers.depth
visualizers.dir
visualizers.discretionary
visualizers.expansion	(no visible effect?)
visualizers.fontkern
visualizers.glue	show whitespace values
visualizers.glyph
visualizers.hbox	draw a box around each line
visualizers.hglue	show values for horizontal glue
visualizers.hkern
visualizers.hpenalty	show horizontal penalties
visualizers.insert
visualizers.italic
visualizers.justification	\showjustification	trac-jus.mkxl
visualizers.kern
visualizers.line
visualizers.makeup
visualizers.marginkern
visualizers.mark
visualizers.math
visualizers.mathglue
visualizers.mathkern
visualizers.origin
visualizers.par
visualizers.penalty	show horiz. & vert. penalties
visualizers.reset
visualizers.simple
visualizers.simplehbox
visualizers.simplevbox
visualizers.simplevtop
visualizers.space
visualizers.strut	show \struts
visualizers.user
visualizers.vbox
visualizers.vglue
visualizers.vkern
visualizers.vpenalty	show vertical penalties
visualizers.vtop
visualizers.whatsit
vspacing.collect
vspacing.page
vspacing.snapping
vspacing.spacing
vspacing.specials
vspacing.synchronizepage
vspacing.vbox
widgets.attachments		scrn-wid.lua
xml.entities		lxml-ent.lua, lxml-tab.lua, lxml-tex.lua
xml.parse		lxml-lpt.lua
xml.path		lxml-lpt.lua
xml.profile		lxml-lpt.lua
xtable.construct		tabl-xtb.lua