Can you help to identify these frames, bikes or parts?

noticed this mark on the on one of the lugs, might help with an i.d

screenshot captor

I know very little about this frame that I picked up on the forum a while back. It's lovely to ride and I'm trying to decide whether it's worth turning into a project or just riding till it fails. If anyone can help with the provenance of this frame I'd be most grateful.

The words Rainbow and Super Sport show through the paint but I can't find anything useful about either online. Can do more pics if needed.

Is that aimed at me?

its a brand.. I was just guessing