https://developers.google.com/search/reference/robots_txt#what-changed
>>Google follows at least five redirect hops.
I know John Mueller has said that in Webmaster office hours, but I don't think I've seen that in help docs before.
>>Google currently enforces a size limit of 500 kibibytes (KiB), and ignores content after that limit.
That's a pretty massive robots.txt. I wonder how many are out there that go beyond that.