About ABI and API... I checked Geany, all default plugins and third-party plugins from https://plugins.geany.org and [Peasy](https://github.com/kugel-/peasy), I found ```SCI_*STYLEBITS*``` in: 1) ```geanylua/glspi_sci.h```, but GeanyLua don't use these messages, this file just have the list of available messages for ```geany.scintilla()``` (sends a ```SCI_*``` message directly to the Scintilla widget of the active document), we just need to update ```geanylua/glspi_sci.h``` and it will disappear. Well, this file needs to be updated after each update of Scintilla. 2) ```peasy/api/geany-scintilla-tmp-1.0.vapì```: as I understood this file can be regenerated too.
I also checked Geany and default plugins by numeric values of messages ```SCI_*STYLEBITS*``` (2090, 2091, 4011).
I.e. changes of ABI and API are not required. Or I'm wrong, because I can not check custom Python and Lua scripts too?
P.S. GeanyLua currently has no maintainer, but I like it easy plugin, my last change is [adding support command "Strip Trailing Spaces"](https://github.com/geany/geany-plugins/pull/759) and I think I can update the```geanylua/glspi_sci.h``` and make PR after updating the Scintilla (also Scintilla 3.10.0 has new ```SCI_*``` messages and other changes, that require update ```glspi_sci.h```).