How to Tell If Porting Lib Is Actually Doing Anything in Your Modpack
Why nothing seems to happen
Porting Lib is a library mod, so installing it by itself changes nothing you can see. It only becomes active when another mod on your list depends on one or more of its modules. If you added it manually and your game looks identical, that is expected behavior, not a bug.
Checking whether it is being used
1. Open your mod list (the mods screen from the main menu or pause menu).
2. Look for Porting Lib entries. Depending on how it was bundled, you may see a single umbrella entry or several module entries such as porting_lib, porting_lib_entity, porting_lib_networking, and similar names.
3. Read the description text on each entry. Modules that are loaded but unused will still appear; they simply sit idle.
4. Cross-reference with your other mods. If a mod's page or its own dependencies list mentions Porting Lib, that mod is the one pulling it in.
What to do if it is missing
If a mod refuses to load and its error mentions Porting Lib, the library is absent or the wrong module set is present. Add the library back, or remove the dependent mod. Do not try to configure Porting Lib itself; it has no in-game options because it exposes code to other mods rather than to players.