It's used in dry cleaning in the USA, and their suppliers will deliver it to you by the gallon [0]. MSDS of course [1]. If you're in Australia and go to the dentist, there's this as well [2] although surely that container with its death's head and POISON label are kept well out of sight. Of course there's the lab supply chain, but that's usually more expensive. It's really easy and legal to get if you want it. I've known many mechanics and similar, professional and otherwise who use workaround sources like these to get the "good stuff" degreaser.
[0] https://garmentcleaningsupply.com/picrin-1-gal-streets.html
[1] http://www.cleanairsupply.com/CleanAir_Web_Image/Chemical/MS...
[2] https://henryschein.com.au/impression/accessories/finale-sol...