New
#1
I would say NO.
In my case, when I create URL shortcut on my desktop to the website, the look of Firefox HTML document icon will depend on if the website using favorite icon. If website is using favorite icon I get white shortcut with the site's small icon in the middle.
If website doesn't use favorite icon I get black shortcut with Firefox logo inside shortcut.
Did it happen to all your Firefox URL shortcuts?
https://en.wikipedia.org/wiki/Favicon
When you save page to your desktop or folder on you hard drive Firefox will created folder in the same location with the same name as your saved HTML page. In that folder Firefox will save a bunch of files, like CSS files, images, JS (JavaScript) files in order for your page to display properly when open that saved page in the browser. BUT, Firefox doesn't save favorite icon file (either image or actual ICO file). That's why you get black icon with Firefox logo inside.
Did it happen after you updated Firefox, or is it just happened some day?
Another conspiracy theory may be is that Mozilla developers changed icon color from white to black.
I have Firefox 62 stable release and if I save page on the desktop my icons have black background color.
If I created "Internet shortcut" the color of FF icon depends if website is using favorite icon.
Here is some info about Firefox ESR:
More info here: https://www.ghacks.net/2018/09/04/fi...e-information/All Firefox channels have received updates: Firefox Stable to version 62.0, Firefox Beta to version 63.0, Firefox Nightly to version 64.0, and Firefox ESR to Firefox ESR 60.2.
The new version of Firefox ESR is a milestone release, at least for Firefox ESR users who are still using Firefox ESR 52.x as the version is no longer supported and Firefox 60.x does not support legacy extensions anymore.
That's part of the new version's design.
They've changed that quite some time ago on regular release but ESR lasted longer until newer major version was released with the change.
Even if the old icon is included in program (firefox.exe), the icon's index or position may be different than before.
To put it short: it needs to be changed via registry.
In this case you need to change the icon of .html file type.
How to change the icon of a file type:
Please Wait... | Cloudflare
Then you need the white file version icon in .ico format to use.
Either extract it from old firefox version, or search online for a good icon/png replacement.
For instance, this looks like a good icon:
New Firefox HTML Icon by Lustmusket3000 on DeviantArt
In case you want to try it out, I've provided for you the ico version in zip attachment.