Another aspect of a CLA is the ability for a company to cover themselves legally. Say I work at MegaCorp (they make heavy use of Go in some backend systems), a

Another aspect of a CLA is the ability for a company to cover themselves legally. Say I work at MegaCorp (they make heavy use of Go in some backend systems), and didn't bother making sure I had permission to contribute on MegaCorp time (and thus, contribute MegaCorp IP). I make some PRs to Go which improve the Go garbage collector, which Google happily accepts. These changes help Google and they could help MegaCorp if some of their projects use Go. Hooray! Somewhere down the line, someone at MegaCorp notices that I've been contributing to Go's garbage collector on MegaCorp time without permission. I may or may not be fired. However, Google has now benefited from what is legally MegaCorp IP without the permission of MegaCorp. If this is in the USA, there's a decent chance that MegaCorp tries to sue Google. That's a headache that I'm sure nobody at Google would want to deal with. If there was a CLA which I had to sign, saying that I had permission to contribute MegaCorp IP, Google has a document clearly saying that I had permission to contribute MegaCorp IP. This is a far better situation for Google than if they had no such document.