Nervous update

Manjaro said it had one update…Electron! So I started it, not paying that much attention to it. Did notice a download phase. Then noticed it was in a build phase. Seemed like it should have been done in maybe 5 minutes.
…still building
looked at my network monitor and something was downloading something?
Maybe some tab in Firefox was downloading? Shutdown Firefox
…still downloading
…still building
Let run another 10 minutes
…still downloading
…still building
At the build phase after the download phase, shouldn’t downloads be finished?
At this point it seems as if it downloaded enough MBs or possibably GBs as the distribution itself. I’ve updated hundreds of programs using pacman and it’s taken less time than this!
There were some other dependencies but still it seemed to me an unreasonable amount of time, especially when the download phase supposedly was finished. I mean really…it’s one program. What was going on? If I was familiar with Wireshark or some other networking tool I probably could have found out. It didn’t have a progress bar just a stupid bar that went right then left, then right then left…and so on.
Anyway, I’m probably overly paranoid but it made me nervous and I finally canceled it. It probably had 20 sec to go!