As in sales clerk. Ring up sales, stock shelves, putter about and put things in order. Read a book or knock out some pushups if it's a really slow day, everything's in order, and the owner's not a dick. That kind of thing.

[EDIT] sense 5 in Webster's 1913. Apparently it is, or at least was, a US usage.

5. An assistant in a shop or store. [U. S.]

I'll second this person's opinion. I used to work in a small town computer shop many years ago as a sales/support "clerk". I spent all day helping people directly, many repeat customers. The job was pretty chill and there was a somewhat new problem to solve every day. I worked fixed hours and when I went home I could completely focus on whatever I wanted to do now that I wasn't working. The wage sucked, slightly above minimum wage isn't great, but it was enough for me at the time.

Contrast that with my FAANG job I have now. The pay is phenomenal. But it basically swallows my life. Between the long hours, weekend on-calls, constant churn, all for a customer I've only spoken to indirectly via a project manager. It's hard to feel like the work you're putting out is really making a difference in anyone's life. With covid and the lack of direct human contact as well, I'd go so far as to say I'm practically pushing commits into a void everyday and getting paid for it, there's very little if any feedback for my work. First-world problems, I know. But if you took away the pay differences, I know which job I'd choose in a heartbeat.