Perused the post 'How Do I Remove Application...'. However the application desired to be removed does not show in the Application Details list, therefore cannot proceed with the delete. See attach.

Do you see this item listed in the handlers.json file in the profile folder ?

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Yes. See attach.

So what now? Any way to remove from the json file?

How customized is your handlers.json file? If you don't see many of your own changes in there, you could rename the file to hide it from Firefox and Firefox should generate a new one at the next startup.

Of course, you also could try to edit the file in a text editor but it isn't easy to see the layout (click the "Raw Data" button in the JSON viewer to see how it actually looks on disk).

The mailto section in handlers.json has an action and handlers key that is an array of name and uriTemplate ("handlers":[{"name":"xxxx","uriTemplate":"https://"},{}]), so if you edit handlers.json then you would have to remove the specific section including a leading or trailing comma (i.e. no two adjacent commas and no comma before the closing '}').

"mailto":{"action":4,"handlers":[{"name":"Yahoo! Mail","uriTemplate":"https://xxxx"},{"name":"Gmail","uriTemplate":"xxxx"}]}

jscher2000, The handlers file is not customized. Contains just three items; Yahoo, Gmail, and the bogus one. See former attach. I can rename it and see what happens. Thanks.

cor-el, Thanks. Using your example, if the Yahoo entry was removed, would the following be the correct edit?:

"mailto":{"action":4,"handlers":[{"name":"Gmail","uriTemplate":"xxxx"}]}

Also, curious, is there any implication for the "action":4 parm? IE, Does that number have to be modified for this type of edit?

Yes, that would be the correct way to remove the Yahoo handler.

You can find the meaning of the action values in this file and for existing mailto handlers there is no need to modify the action. You can look at other items in your handlers.json file to see what actions are used in each case.

• https://searchfox.org/mozilla-release/source/netwerk/mime/nsIMIMEInfo.idl#line-101

saveToDisk = 0;
alwaysAsk = 1;
useHelperApp = 2;
handleInternally = 3;
useSystemDefault = 4;

cor-el, jscher200, FYI, During the interval I found something else which may be of interest. My bogus handlers entry was referring to the Windows Temporary Internet file location. On a hunch, I cleared all Windows temporary items. That removed the bogus file. Subsequent mailto display no longer showed the bogus entry; though initially the bogus entry still existed in the handlers file. But eventually after mozilla restart the bogus entry also was removed from the handlers file.