Current (0fa29a0) implementations of get_lexer_by_name and some other similar functions don't take priority of the lexer into consideration and return the first lexer with the matching name. This implies that plugins are never checked if there's a builtin lexer with the given name.

Checking all the installed lexers and matching based on priority or other heuristics that are already implemented for guessing lexers based on content etc. can enable users to override some of the builtin lexers with their own custom ones by assigning higher priority to their lexers.