@p-linnane vctool worked great here, you should be able to add future betas with it :)

Here's the command I used to add this one:

/Applications/VirtualBuddy.app/Contents/MacOS/vctool catalog image add \
-i https://updates.cdn-apple.com/2025SummerSeed/fullrestores/082-55592/95F6DA16-4116-491E-B332-7165C051E1C5/UniversalMac_26.0_25A5279m_Restore.ipsw \
-c devbeta \
-n "macOS 16.0 Developer Beta 1" \
-o data/ipsws_v2.json

Awesome! Are you open to me setting up a GitHub Action to run this?

Awesome! Are you open to me setting up a GitHub Action to run this?

Tell me more!

Over in Homebrew land we have a couple manually dispatchable jobs to open update PR's: https://github.com/Homebrew/homebrew-core/blob/master/.github/workflows/dispatch-build-bottle.yml.

Could configure it to take the URL and handle everything else. Totally fine to just keep operating the normal way though. Your call!

Shouldn't the name be macOS 26.0 Developer Beta 1?

Shouldn't the name be macOS 26.0 Developer Beta 1?

Thanks for catching this. I've opened #525 to fix the name. Apple loves to keep us guessing 😅