|mach try| requires specifying which platforms to run it on... except doesn't document how to do that. The --help docs list what the -p switch does, but not what you can pass to it. Which leaves me not knowing what to put there (is it win? windows? win32? windows64? windows-64? win-64?), without having to look online... somewhere. And yes, this is known via institutional knowledge, and no that does not count.