I think this is a great development in terms of building norms and community around this very common and crucial role. I've been fairly insulated from a lot of the politics, but I'm starting to realize I need to learn a few more skills in that area.
I'm also a staff SWE (not at Google) and I find it hard to believe there are no resources for senior+ ICs in a place that's supposedly engineering-driven. I've been bombarded with 'leading without authority' and 'influence'-like trainings since forever in my current workplace...
Managers have a network: lots of manager-focused meetings, trainings, perf rating calibration sessions, etc. Even if they don't work on the same projects they'll have much more interaction than ICs and TLs have which each other. ICs and TLs who work on different projects have to seek each other out, and there's no official forum for this.
The resources are certainly there at Google, but you do have to dig them up yourself. If you're a manager you're required to do them.
If you're a manager who hasn't taken Managing Within the Law or whatever, you may get in trouble, but as an IC you don't even get the option!
You can go on grow and search for "classes on leadership" or whatever else you're looking for and it will appear. It's not like you have to guess the title ahead of time. Grow is quite literally a course catalog.