One of the tools we use in MDS is LoginLog, a macOS app that shows progress over the login window. Originally written by the awesome Per Olofsson, it shows /var/log/install.log (but you can specify any log you like).
With the recent changes in macOS, Python has been removed as a default install. In order to keep using this tool, we ported it to a compiled macOS binary (written in Swift). It is still open source (Apache License) and the configuration file should be the same: it’s an easy, drop-in replacement if you are already using LoginLog. It should work on macOS 10.10 or later, is Intel and Apple Silicon native, and is signed and notarized.
Check out the repository at https://bitbucket.org/twocanoes/loginlog or click on the big “Download Now” button below to download the latest build: