While playing with Perl setup I by accident found multiple setups can be specified on command line like:

ikiwiki --setup COMMON.setup --setup MY.setup

Could this be an official feature, in which case it would be nice documented or an "undocumented one" to avoid?

What about Perl setup files which are undocumented but in the source code. I have found out after all...

See also:

• Best way to share settings between repositories
• support includes in setup files