How to get more info regarding Legacy System Extensions in MacOS Catalina?

Question

With the upgrade to the most recent version of MacOS Catalina 10.15.4 (19E287), I received a handful of warnings about this or that legacy system extension:

• Legacy Developer: Sierrawireless
• Symantec
• Ploytec GmbH
• Legacy Developer: Novatelwireles
• Legacy Developer: Rim
• Legacy Developer: Lge

The "More Info" button takes one to this Apple Support Page. Some of these look suspiciously old to me, particularly the "Legacy Developer" ones. Rather than "contact[ing] the developer", I'd like to see more information about these extensions and determine two things:

1. Is this extension related to an app (which I may no longer be using)
2. How can I remove, safely, an unwanted system extension.

So, any information on how to dig deeper and act upon into these warnings would be appreciated.

Answer 1

Use System Report

The following worked for me:

1. Click on the Apple icon then About This Mac
2. Click on System Report
3. In the left column, Click on Software > Extensions
4. (Be patient -- it might take a while to load up the info)
5. Click on the Obtained From column so you can skip over all the Apple provided extensions
6. Look at each extension NOT provided by Apple. If the Dependencies field is Deprecated, you probably can (and should) remove it.

P.S.: A similar technique for Applications (see step 3 above) lets you quickly find all 32-bit applications, which will also be unsupported going forward.

Answer 2

Don't panic. Your Mac will continue to work fine. Check out these two links. They have good info on the subject:

https://www.idownloadblog.com/2018/06/19/legacy-apps-macos-mojave/

https://www.macrumors.com/2020/03/25/mac-legacy-system-extension-warning/

I was able to find the culprit apps in different folders, and once identified as really useless (RIM for example), I dragged the containing folder to the trash and voilà.

Other apps may just need updating, like Norton and Symantec.

Good luck.