VIM variables: $VIMRUNTIME

The (environment) variable $VIMRUNTIME points to the directory that contains the runtime files that are distributed along with vim.

Usually, the value of $VIMRUNTIME is not explicitly defined by a user.

If the variable VIMRUNTIME is not defined, vim tries to determine the runtime directory in the function vim_getenv() by using the value of the

• helpfile option
• the name of the executable (argv[0] and/or global variable exe_name)

The value of the global variable default_vimruntime_dir seems to be a fallback value.

If vim determined the value for $VIMRUNTIME, it also sets the value of didset_vimruntime to TRUE.