According to my calculations, this means Firefox 100 will be released on 2022-03-08.
Neither says anything useful. 2019-10 is no more actionable or informative than 76.0.0. That 2019-10 was released in october 2019 is meaningless information and only "more" in the "babble" sense.
I would know it there is a big chance of breakage if I moved from 76.0.0 -> v77.0.0 and I am reasonably certain it won't break if I moved from 76.0.0 -> 76.0.1
Since there are more websites than extensions, the utilitarian approach would be to choose 2019-10 over 76.0.0.
Furthermore, as another comment said, it is impossible to remember on which release they started breaking this or that, since there is no more major version number change, which is usually handy to indicate backward-incompatible changes.
On one side, relatively minor upgrades can have huge impacts for some use cases. Some changes are riskier than others, but SemVer and major/minor distinctions are not reliable signals for anything critical.
More important though, if you're skipping browser updates at all, you need to be tracking the security implications of every patch you skip. Otherwise you're increasing your risk by an order of magnitude more than you'd reduce it by deciding a change might be too buggy based on a numbering scheme.
It's not so fun to work around because Windows Installer tries to be smart about things, as opposed to the others that take a more robust approach.
https://docs.microsoft.com/en-us/windows/win32/msi/productve...