Where can I find what characters are valid in an X11 config file
I'd like to name my identifier
libinput touchpad disable tap-to-click but I don't know if hyphens are valid.
I'm running Manjaro Linux.
I don’t think there are any particular restrictions, apart from the use of quotes; the configuration file manpage doesn’t mention anything specific. Looking at the parser source code, a string can contain anything apart from double quotes, carriage returns, newlines and the null byte.
You should certainly be able to use hyphens.