why the api is different with the open endpoint?

[earth-2022]

I am a new guy,I am confused about the DOC
here is the testnet open endpoint,api list is below,it is different from the offical DOC https://node-rpc-docs.celestia.org/?version=v0.14.1，
why they are so different?
where is the DOC about open endpoint?
I am very thankful if someone can give me some advises.

https://celestia-testnet-rpc.blacknodes.net/

[Ferret-san]

that's a celestia core endpoint, openrpc is to communicate with a light node, which you can run here