That looks like an internet shortcut file that would open the link in the default browser like other internet shortcuts if you double-click this shortcut. Not sure about the gsheet file extension.

If that isn't working for some reason then paste the url value (https://docs.google.com/...) in the Firefox location bar.

Hmm, I've never heard of a .gsheet file.

Do you have a Google Drive program installed on your system that normally would turns that shortcut information back into a valid URL? Or would that be Google Chrome?

In Firefox, where the .gsheet file contents are displayed, if you select the URL starting with https://docs.google.com/ up to but not including the quotation mark, then right-click it, and choose Open Link in New Tab, does it properly link to the sheet in Google Drive?

cor-el said

That looks like an internet shortcut file that would open the link in the default browser like other internet shortcuts if you double-click this shortcut. Not sure about the gsheet file extension. If that isn't working for some reason then paste the url value (https://docs.google.com/...) in the Firefox location bar.

I understand I can simply copy and paste the link, but how can I double click and open with Firefox to have to automatically open?

That gsheet link is probably a leftover from the past (2016) when you still had the Google Desktop application that would open the linked file in the default browser. As Google discontinued this application you will have to extract the link and paste the link in the location/address bar of a browser to access the file like posted above.

See also:

• https://fileinfo.com/extension/gsheet

techcrium said

I understand I can simply copy and paste the link, but how can I double click and open with Firefox to have to automatically open?

An add-on or userscript could detect that a .gsheet file loaded, find the link, and navigate the tab to the linked page. For example, here's a user script that should run in Tampermonkey, Violentmonkey, or Greasemonkey (only tested in Violentmonkey):

https://greasyfork.org/en/scripts/397217-load-gsheet-link-from-local-file

I downloaded this file for testing: https://resources.oreilly.com/examples/0636920048503/raw/11f284105fdb36ec9b75d5cfcf9a115bf0171abe/Google%20Apps%20Script%20for%20Developers%20-%20Working%20Files/Chapter%201/ideData.gsheet

I've been syncing my Google Drive to my 2019 MacBook Pro (macOS Catalina version 10.15.4 using Backup and Sync from Google. Up until this morning, I've been able to navigate to a Google Docs file on my machine via a Google Drive folder that's locally synced in Finder on my machine, double-click on it, and have it open in Firefox. No add-ons necessary. Today, it suddenly seemed to stop working. In my attempt to troubleshoot I checked my default Finder settings for Google Docs files (i.e. all files ending in .gdocs) and found that they were set to be opened with Backup and Sync Sync, which I thought was weird. I thought, "duh, these files are supposed to be opened by my browser," so I set the default behavior to "Open with" Firefox. To my surprise, Firefox opens a browser window, but it's not the Google Doc—it's exactly the error mentioned by the OP.

Any ideas why this might've worked in the past but no longer does, and any suggestions for a non-addon solution?

To my surprise, Firefox opens a browser window, but it's not the Google Doc—it's exactly the error mentioned by the OP. Any ideas why this might've worked in the past but no longer does, and any suggestions for a non-addon solution?

I don't think it's an error, I think it's the contents of the file. Something is missing that previously read the URL in the file and loaded it. But I couldn't tell what that was.