How to add meta info to stored .html files e.g. tags

I’ve moved a collection of .html files from the excellent SingleFile browser extension into my Obsidian vault. HTML Reader displays them very well, and I can search their contents with OmniSearch. What I can’t do is tag them, or add other meta information commonly stored in the front matter.

Is there any way to do this? The original URL and tags are my top priorities.

You could try the Binary File Manager plugin, which adds a companion note for each non-note so you can add tags and whatnot.