Current Googler -- AFAIK, 20% time is still a thing. You just have to clarify the project with your manager, just like you did before. I utilized it to write the Mendel development tool (mdt) for Coral boards here: https://pypi.org/project/mendel-development-tool/
On my current project, I have other Googlers spending 20% time to help the team I lead as well.
120% is a misconception. 20% is volunteer. 80% is assigned. I built MDT that way, taking a few days cumulatively to work on it, and I maintain a strict 40 hour work week, with my manager's backing.
On my current project, I have other Googlers spending 20% time to help the team I lead as well.
20% is very much still a thing here.