"Unity" prefix in custom package asmdef name

Over here there are some examples of how to name asmdef files, e.g. “Unity.[YourPackageName].asmdef”, etc.

Question: Is this “Unity” prefix actually allowed/encouraged? Or are we supposed to use a custom prefix, to avoid making it look like the package was developed by Unity? The linked documentation is a bit unclear about this imo…

According to this 1: It seam to be more a convention than an obligation. But is encourage you to use the unity convention

I sent an email to trademarks-team@unity3d.com and got this reply:

Thank you for your email to our Trademarks inbox.

We have reviewed your concern - thank you very much for highlighting the inconsistency in our Documentation. Our documentation team has reviewed the relevant areas of the manual and has done the following:

- updated the [Package Layout][1] page to make it clear that the first element of a package name should be 
- added a note to the [naming a package][2] page to let users know that the examples are based on Unity packages and they shouldn't use the 'unity' prefix in their package name.

These changes will be effective from 28 September after the site’s next build.

I hope that helps clarify that unity should not be used as a prefix in custom package names.