Chainlist.org
Linea Sepolia Testnet is listed on the official ethereum-lists/chains repository that is pulled by many cross-chain projects like chainlist.org, thirdweb, and Cookbook.dev.
You can get access to different key parameters for the Linea Testnet chains like:
- chainId
- RPC Endpoints
- Native Currency settings
- Explorer info
- ENS info
- Linea Network Icon
See the official repo here