Archived KimimaruTCRF video from YouTube. Original description mostly intact:

This video shows dialogue said by Saria via Saria's Song that cannot be seen under normal circumstances.

The conditions are outlined on TCRF (https://tcrf.net/The_Legend_of_Zelda:_Ocarina_of_Time/Unused_Text#0164). You must complete Jabu-Jabu's Belly without getting the Goron's Bracelet, then talk to Saria through Saria's Song. This is impossible in a normal playthrough since you need the Goron's Bracelet to get Bombs, which are required to enter Zora's Domain and thus Jabu-Jabu.

To try it out for yourself, play the game normally until obtaining Zelda's Lullaby and Saria's Song. Afterwards, you can bypass the rocks in Zora's River by clipping into the loading trigger to Zora's River's shortcut from the Lost Woods area (aka Aquascape). You're set from thereon, as you're able to get into and complete Jabu-Jabu normally without any issues.