Changes

Temporary values and definitions often start with two <code>!</code> markers, and macros that represent internal strings normally start with a single letter followed by a single exclamation mark, for example: <code>\v!off</code> stands for the meaning of ''off'' in the current interface language. More on this convention can be read in [[System Macros/Scratch Variables]].

The protection and unprotection commands can be nested (unlike <code>\makeatletter</code> in LaTeX). This nesting ability is a convenience, since it allows one to use the protection pair regardless of whether protection is already turned on. It is a very good habit to always start your macro files with <code>\unprotect</code> and end them with <code>\protect</code>, even if you don't need to access internal commands right away.