This is a completely free and compatible alternative to other replacement brackets which are being sold at ludicrous prices.
I created this model in collaboration with someone who was looking to sell their SA-30 roll adapter but were missing the plastic attachment bracket. The bracket interfaces between the back of the scanner and the roll adapter (see the screenshots from the manual), and is necessary for the adapter to mount properly on the back of the scanner.
We modelled this part from an existing bracket and have tested the fit between an SA-30 and a Coolscan 5000. The test print was printed from PETG and appears robust enough.
The author marked this model as their own original creation.