Thanks for the hint/prompt Moonchild - that worked pretty easily!

Still on a steep learning curve with Add-on construction here, taking simple ones apart, reading "make your own Add-on" tutorials, altering small items, putting Humpty-dumpty back together again, etc!
Procedure with latest Norton Internet Security (NIS 2013 v20.3.1.22) installed:
Locate the Norton Vulnerability Protection (NVP) Firefox Plugin folder which is called "IPSFFPlgn" in Norton NIS application:
My IPSFFPlgn location - C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NIS_20.2.1.22\IPSFFPlgn
NOTE: ProgramData is a hidden folder - ensure "show hidden files and folders" selected in Control Panel > Folder Options
IPSFFPlgn folder.JPG
- Copy "IPSFFPlgn" folder to Desktop (it's an ordinary folder - the "unpacked" version of the add-on (flat file structure) as Moonchild suggested).
- Open "IPSFFPlgn" folder, Select All (however you normally select multiple files) > Right-click (on any of the 5 highlighted files) > Select "Send To" > Choose "Compressed (zipped) Folder" option. Rename the newly created "xxxxxx.zip" folder as "IPSFFPlgn.xpi" (or "any name.xpi").
- Drag new IPSFFPlgn.xpi folder onto Desktop. Close copy of original IPSFFPlgn folder, delete or keep as you please.
- Install NVP Add-on "IPSFFPlgn.xpi" into Pale Moon by normal methods, either drag "IPSFFplgn.xpi" onto any open Pale Moon window, or in Pale Moon Add-ons Manager > Click Gearwheel symbol (top right) > Select "Install Add-on From File..."
BTW: Not actually seen Norton Vulnerability Protection (NVP) working in Firefox - assume it's similar concept to Mozilla/Google Safebrowsing?

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