It is documented in [the manual](https://www.geany.org/manual/current/index.html#regular-expressions):
\n | Where n is 1 through 9 refers to the first through ninth tagged region when searching or replacing. Searching for (Wiki)\1 matches WikiWiki. If the search string was Fred([1-9])XXX and the replace string was Sam\1YYY, when applied to Fred2XXX this would generate Sam2YYY. -- | -- Maybe it needs to be called-out more, since the GLib docs don't do a good job either. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/geany/geany/issues/2439#issuecomment-586706966
