License Name
bilibili Model Use License Agreement

License Homepage URL
I could only find it at https://github.com/index-tts/index-tts/blob/main/LICENSE for now.

Reference URLs
Discovered through https://github.com/index-tts/index-tts

Notes
They currently use LicenseRef-Bilibili-IndexTTS inside their own package metadata.