4.3 Ownership. As between you and Adobe, you (as a Business User or a Personal User, as applicable) retain all rights and ownership of your Content (or where applicable, you must ensure that you or the Business (as applicable) have a valid license to the Content). We do not claim any ownership rights to your Content.
4.4 Sharing Your Content.
(A) Sharing. Some Services and Software may provide features that allow you to Share your Content with other users or to make it public. “Share” means to email, post, transmit, stream, upload, or otherwise make available (whether to us or other users) through your use of the Services and Software. Other users may use, copy, modify, or re-share your Content in many ways. Please carefully consider what you choose to Share or make public as you are responsible for the Content that you Share.
from here:
https://www.adobe.com/legal/terms.html#content
As promissed... today I received an official answer from Adobe... below is translated version:
"I hope you are doing well. I consulted with my supervisor regarding your inquiry about the audio tracks in Premiere Elements, and indeed, we do not have such information. However, if they are free audio tracks, they can continue to be used. I hope this information was somewhat helpful, and should you have any further questions or matters, please feel free to contact us at any time."