Don’t think so — you just sorta know what you’re getting after each link in this chained call and what you can build atop. It’s all basically just a few simple principles. Whoever’s coming from software engineering background might have encountered already under the name fluent API. Or at least see a similarity with Builder pattern. See https://en.wikipedia.org/wiki/Method_chaining for the general idea.
Also usually you’d have long expressions like this one split up into separate columns to calculate intermediary steps. Not this one though, this one is pretty valid, as there’s not much to extract.
There’s this basic lesson with a video though. May be useful if you’re used to the excel style of writing formulas like Unique(ListCombine(Filter(thisRow.Tasks, Status = "In progress").Users)):