I'm not sure if Jetbrains is bigger than I expected or Gitlab smaller, but it feels to me that Jetbrains wouldn't be able to afford Gitlab.

It would be roughly a merger of equals (1-2 billion either direction), and I'm not sure how that could be financed without JetBrains giving up too much control over their own existing company. Perhaps a bank could extend a private loan if they believed in JetBrains ability to use the merger to grow both sides of the merged company.

Gitlab is worth $10B on the public market right now without an acquisition premium. You're very far.

Ah wow, my apologies. I didn’t realize it was publicly traded! I used very inappropriate sources for that valuation…most likely super outdated without realizing it.

Jetbrains decided to go from the Space product to a cut down Space Code product with just code review and git hosting, but then this last week announced they will be shuttering even that next year. I doubt they want to get back into the git hosting, if they did by buying GitLab, that would be odd.