For examplehttps://symfony.com/doc/current/service_container/tags.html#tagged-services-with-priority
There we can see example of setting priority. But no description possible values of priority and how this value processing, and how it affects order of tagged elements.

But instead of previous article here this description presents.
https://symfony.com/doc/current/reference/dic_tags.html

Also many components has lack of different examples and use cases.