What it does
ATEM Setup is 4.1 GB, and 3.4 GB of that is firmware for every ATEM switcher and panel Blackmagic makes, including all the ones you'll never own. atem-slim copies it without that firmware, or with only the firmware for the models you name, and puts ATEM Software Control next to it unchanged. ATEM Software Control has no firmware in it to begin with; it comes along so the folder has both apps.
It's one zsh script and needs nothing a stock Mac doesn't already have. It reads which models each firmware file is for from the file's own header, copies the rest of the app, and signs the copy for the Mac it runs on, because Blackmagic's signature covers every file and a copy with files missing fails it. The apps in /Applications are only read.
- Lists every firmware file by USB product ID, with its size and the model where it's known
- Keeps the firmware for the models you name, or for whatever Blackmagic kit is plugged in over USB
- Copies ATEM Software Control alongside with Blackmagic's signature intact
- Signs the slim ATEM Setup for the Mac it's made on
- Won't overwrite or clear a folder it didn't make
- Slim ATEM Setup is 755 MB with no firmware, 847 MB keeping one model
Where it stands
Not tagged yet, so it runs from the repo. Tried on macOS 26.4.1 against ATEM Setup 10.2.1: the listing, the copy, the signing and the refusals all work, and a slim ATEM Setup opens to "No ATEM found" both with no firmware and with one model's. No switcher has been connected to a slim copy, to set it up or to update it, so what it does when it meets a switcher whose firmware you dropped is still a guess (probably no update on offer). Reading connected devices has only been tried against a sample of macOS's USB listing. The slim copy is Blackmagic's software with parts taken out, so don't share it: share the script, and let everyone run it against their own install.