The businesses and organizations listed in the “Licensed to YouTube by” field are the music rights holders who have agreed to allow YouTube to use identified music in official and user-generated videos, and share in the revenue those videos earn on the platform. For example, if you see an ad on a video that contains music and has “Music in this video” information, the labels and publishers listed under “Licensed to YouTube by” are earning a share of the revenue generated by that ad.
In addition to music labels and publishers whose names you may recognize, you may see that some songs are “Licensed to YouTube by” a number of “music rights societies.” This refers to organizations that collect royalties on behalf of their songwriters and publishers around the world. Just as with individual music publishers, YouTube has license agreements with these entities and shares revenue with them for videos they claim.
Learn more by visiting YouTube's Help Center: https://support.google.com/youtube/answer/7680188?hl=en
Here is an example of what that might look like