Note that it was piled up when the Eclipse settings were broken and recreated. I don't know if the method of installing the Tomcat plugin has changed or it's because of my environment, but I couldn't rely on the googled information, so I'll write it down.
Even if you look at the procedure manual and the information on the net that was in the company, "https://sourceforge.net/projects/tomcatplugin/files/ Download the plugin from and select .zip " It says, but it's not zip that you can download. I can't install it even if I compress it to zip.
So, when I looked up various things, it wasn't downloaded from the above link,
Then restart Eclipse and the Tomcat item will be added to Eclipse> Preferences. Versions ranged from 3.3 to 9.x, so this should be fine in most cases.
I don't know, but I feel like I'm googled and piled up with this procedure every time ...