I need to see what my Plugins are doing!

So, some amount of time ago, i used a command to see what any of my plugins was doing on the server in my cmd, so, tried searching that on the internet but found nothing. Ande here am I, guys, if u know how to enable this to make visible, let me know please. I just want to remove a Welcome message on purple that pops up everytime a new player log-in. I disabeld it on Essentials but nothing, thats why i need to see what every single one of my plugins is doing, just to know what plugin is doing this. Thx for every help. (Im on 1.16.5)

Possibly running /timings report after the event in question could help you, as it shows what event causes plugins to run. Anything listening on PlayerJoinEvent or similar could be a possible culprit.