In the case of Juce, it’s quite easy. When you are at the Juce Github page, click “Tags”. Go back to version 4.2.0. There’s a zip file you can download. (I made a mistake in my last post, I said 3.2.0 was the last version with Introjucer, it was 4.2.0)
If you just want to see the files: Click the tag number and again click the tag number with the tag symbol next to it. Otherwise, click the long number (70949aa) and then browse files in the big blue bar at the top.
For Ctrlr. Go to the commit you want to download. For instance on this page:
https://github.com/RomanKubiak/ctrlr/commits/stable?after=2f9ce2ea74e49cb324442eae530b74aff59c35f2+139&branch=stable
scroll down to the commit of April 29 2016. Click on the <> at the right hand of the window. And then under “Code” choose Zip.