Every hobby or job has its own niche tools and if you're not part of that community, you may not recognize something it you came across it.
Like, if someone went through my writing desk, they'd find tiny sheets of brass, a loupe, cotton swabs, silicon grease, and blunt syringes. They'd be forgiven if they thought I had some illicit habits, but those are actually common tools for the cleaning and maintenance of fountain pens.