Is there an official logo that I could use to advertise that my app is using Panda3D as engine ?
There a a few images in the rebranding topics here on discourse and some scattered on the website, but I would be nice to have them available at one location (and officially approved 
)
Iāll second that. A press kit or at least the logo in various sizes would be very useful.
If you carefully read the license, then it can be interpreted in the opposite direction. You do not advertise Panda3d, but promote your product with the help of the name Panda3d.
The license only states in point 3, that you should not use the name Carnegie Mellon University or of any of the contributors. Thereās nothing about the usage of the engines name nor logo itself.
Carnegie Mellon University is the creator of the name and logo of the engine. Maybe I read a different version of BSD, most likely a general one.
As the license on the website says āname of Carnegie Mellon Universityā it only means that you should not use the name Carnegie Mellon University, not names made by CMU, esp. as the name Panda3D was made up by Disney, not CMU as far as I know. In my opinion it wouldnāt even make sense to forbit people to tell others their games were made by Panda3D while on the other hand it makes total sense to forbit them to say Disney or CMU are endorsing the making of some games by only using their open sourced engine.
PS.: The official license of P3D can be found here if you havenāt found it yet: https://www.panda3d.org/license/