Geany parsing to extract symbol infomration

Question

I want to alter Geany configuration to change how markdown is parsed:

1. Sidebar Symbols list only displays headings 2 and 3
2. fold points for headings 2 and 3

The Geany documentation hints that it can be done:

"supported filetypes are parsed to extract the symbol information (aka workspace symbols)." Geany Manual, 2021

How does Geany parse files?

1. language keywords, are editable via Tools > configuration Editor > FileTypes configuration
2. Pattern matching File for functions, how?
3. Pattern matching files in Project folder for functions, how?
4. ... are there others?