A question aboout postgresql-server-dev versions

I am using Postgresql version 11 on Ubuntu 18.04. I am considering using an
extension called libphonenumber. It needs Postgresql-server-dev to build. I
found postgresql-server-dev-all in the list of available packages, BUT when
I ask apt-get to lad it, a dependency is postgresql-server-dev-10. 

Seems wrong, is this OK?


-- 
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
                        -- Benjamin Franklin