Learning PEI but also important things about languages: inflection, casing, etc: Start at https://youtu.be/kzP5Lq9fYi8?t=475
World Atlas of Language Structures (WALS) is a large database of structural (phonological, grammatical, lexical) properties of languages gathered from descriptive materials (such as reference grammars)
Syntax for systemd files
Highlight eshell syntax on command line and in script(?)
Everything starting with # like #
