@sod You're the plugin guru, so decided to go straight to the source. How difficult (or even possible) would it be to create a "Support Plugin." When installed, it creates a page (support.txt or similar) that could list as much information as possible. Such as: Theme/plugins installed, theme/plugins version, link to the custom.css (that one's easy, I know), link to full site. Maybe even things like last build time. That's beyond my expertise but would be really helpful when trying to work through problems others have.
@Mtt Oh, my, you think way too highly of me but thank you. I'm putting plug-in guru on my business card now. š It's possible to create dynamic files in Hugo using the assets pipeline and resources.ExecuteAsTemplate.
So, for example, one could put a file named support.txt in the assets directory and add template code in the same way as with theme templates. I'm doing this with the file documents.json in my Search Space plug-in. But, in that case, I'm listing the blog's posts instead of metadata.