Listening to Events (CommonSubscriber missing)

My Mautic version is: 3.0.1
My PHP version is: 7.3

My problem is: I tried to listen to events from a custom plugin I developed (based on MauticExtendeeFormTabBundle) the
class name is InjectCustomContentSubscriber and extends from CommonSubscriber as this is the only example I have from other plugins, to extend CommonSubscriber yet that file is no longer present in Mautic 3 CoreBundle

These errors are showing in the log:
Class “MauticPlugin\CoreBundle\EventListener\CommonSubscriber” not found while loading “MauticPlugin\PulseEvents

Steps I have tried to fix the problem:
Tried to extend other classes or implement the interface EventSubscriberInterface

No luck, if someone can provide a sample on how to listen for events specially the VIEW_INJECT_CUSTOM_CONTENT from a custom plugin that will be greatly appreciated.

Thank You!

Hello @ismaescamillaa, and welcome!

Can you tell us where you are in your research since your initial post?