What are the Ubiquity logs on my Mac?

Ubiquity or Ubiquitous Data File is how iCloud shared documents get synced between your various devices and the cloud storage servers Apple runs. It’s a legitimate part of the macOS, but that doesn’t mean that the files you saw were legit as sometimes scam software like malware reuses a “safe” name to “hide in plain sight” so that someone would find my answer here or Apple’s documentation and conclude all is fine.

The most likely situation for you is all good, but we’d need to look at the detailed file to know for sure.