These extra menus showed pd and external objects (each in another section) ready to be added in the patch.

Here is a small sketch I made to explain myself better:

Of course, I did a search on the internet trying to find this external but the vastness of pure data libraries and not knowing its name made it difficult to find it.

Do you think you know what it was called?

On the other hand, it doesn't matter if I open the patch All_about_else.pd or declare the start path, it doesn't open at all.

I also noticed that my version of pure data is old (0.53-1); I guess this must affect; the Debian system repositories install this version by default, so I'll see what I can solve this before I update further on my problem.
Thanks for all the advice.

It's just a probability, as Debian is a very insistent system in not using programs that have not been marked as stable in its repository. So I might as well just wait for the next version of pd for my system and see if that solves my problem..