Newer FTB packs don't show up in the instance creation wizard

[GG3Hahn]

Operating System

Windows

Version of PolyMC

PolyMC develop e846551 (Sep 12 2026)

Version of Qt

Qt 6.11.2

Description of bug

There are FTB modpacks which show up on their website/app but not in PolyMC, e.g. FTB Unstable 6

Steps to reproduce

1. Click Add Instance
2. Select FTB as the source
3. Search for a modpack with an id >126, e.g. FTB Unstable 6

Suspected cause

Packs are no longer indexed/hosted on modpacks.ch. Instead, FTB employs their own API and modpack manifests that contain direct download URLs.
See https://api.feed-the-beast.com/v1/modpacks/modpack/132/100499 (mirror) for an example

This issue is unique

• I have searched the issue tracker and did not find an issue describing my bug.

[GG3Hahn]

Relevant Prism PR for reference: PrismLauncher/PrismLauncher#3559