\startenvironment ... \stopenvironment
The environment \startenvironment ... \stopenvironment is used for ...
|\startenvironment[...] ... \stopenvironment|
|\startenvironment ... ... \stopenvironment|
A \startenvironment block contains setups that should be loaded when the file is invoked with \environment. The first argument (given without square brackets!) is the name, and can be anything as long as it's not empty (the filename is a common choice). This name is used by ConTeXt internally when keeping track of how often the environment has been loaded, and it is used when printing output to stderr/the log file, as follows:
used structure > text: mytexfile used structure > environment: myenvironment
Within a \startenvironment block, the commands \project, \product, and \component are ignored; other environments can be loaded using \environment.
The environment file:
% env_packed_items.tex \startenvironment some_label \setupitemize[packed] \stopenvironment
A file that uses that environment:
% myfile.tex \environment env_packed_items \starttext bla bla \startitemize \item \stopitemize \stoptext