The blog post regarding this “dump” suggests that it was actually from malware, so the answer to “Does that mean malware was once on your system?” is likely to be Yes. https://www.troyhunt.com/processing-23-billion-rows-of-alien-txtbase-stealer-logs/

Use the ‘Notify me’ option and verify your email address, and then it will show the expanded list of domains that were exposed from the malware:

Street Complete is a great app for quests regarding existing features, but also consider the feature might not exist at all yet in OSM.

Map Complete is great for adding new features. It also asks a bunch of optional simple questions about the feature which gets converted into the relevant OSM tags. It’s browser based but you can just add a shortcut to your home screen to have it quickly accessible.