The question says it all. I'd like to install https://github.com/lochmueller/staticfilecache in a non-composerified TYPO3 instance. What is the recommended procedure?
I thought I could download the source, cd into it and then do composer install on the command line and then I would get the complete extension. But I didn't see that worked.
You could ask the author to add support for the TYPO3 Classic Mode which basically means embedding dependencies for extension packages uploaded to the TER. There is no other way to achieve this in Classic Mode, thus obviously I strongly recommend switching to Composer Mode.