The instructions in DEVELOP.md under “How to add a new language” are outdated.

[Egor-OSSRevival]

They reference src/lang.c for adding a new LANGUAGE_LIST[] entry, but this file no longer exists.
The corresponding code now lives in lib/lang.c, so the documentation needs to be updated to reflect the new file location.

[Syed-Shahrukh-OSSRevival]

#87