I just checked the Scintilla source code … even their most recent version doesn’t appear to have Go – ie, I couldn’t find LexGo*.cpp in the source code, so unless there’s some other name other than Go or Golang that the language goes by, someone would have to make a Scintilla Feature Request to get the ball rolling.

Update: https://sourceforge.net/p/scintilla/feature-requests/750/ shows “they” won’t do it. Though if i read correctly, “they” might allow someone else to contribute the lexer to their codebase.

To add native Golang lexing support, Scintilla would need to add it, then the Notepad++ developers would have to spend the effort to upgrade Scintilla.

But remember, one of Notepad++'s features is User Defined Languages (“UDL”). The UDL Collection appears to have a UDL for Go, or you could make your own.

For more on the UDL feature of Notepad++, see the docs:

• official summary: https://npp-user-manual.org/docs/user-defined-language-system/
• detailed guide: https://ivan-radic.github.io/udl-documentation/