The 'video downloader helper' is an add-on.

Customize Firefox controls, buttons and toolbars {web link}

Type about:customizing<enter> in the address bar.

Note: about:customizing is no longer present in Firefox 47+ releases.

• Press Alt or F10 to bring up the Menu Bar.Then View > Toolbars > Customize.
• Right-click on a blank spot in the toolbar and select Customize.

In the new window, look for the icon. When you find it, hold down the left button on it, and move it to where you want it to be. You can move any of the icons you want from here, but; some icons are locked in place.

There is also a Restore Defaults button at the bottom middle.

Thanks Fred , it took me a longer time because I had to translate the terms in French as I use that version.

Glad to help. Safe Surfing.

I have Firefox 92.0.1 (64-bit) on my Apple MacBook Pro computer.

I have Video DownloadHelper installed. I see it in the Extensions section of the Add-ons Manager; it is activated.

I don't see Video DownloadHelper in the list of items in the Customize Firefox app.

How do I solve this problem?

The icon looks like two balls side by side. They might be in black and white. Have you checked the toolbar overflow? re: >>

You can reach its options via the Add-ons Manager.

I finally found the Video DownloadHelper icon in the Add-ons Manager. It appeared in the manager after I opened the Firefox Web Developer Tools and saw some errors (see attachments). I don't know what I did, but whatever I did fixed the problem of the missing Video DownloadHelper icon.

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems. Go to that post and click the 'Solved' button to its right.