This is about what happens when you have 2+ favicons in your head element. This is tested on Firefox on current Ubuntu. Animated GIF icons are not compatible with everything so this is important at least if you want an animated icon. I have found that gugquettex.com/favicon.ico always is displayed so not gugquettex.com/icon.gif regardless of order when those are only two. I have found that gugquettex.com/favicon.png is displayed when after gugquettex.com/icon.gif but other way when put before. Note no errors are with 2+ icons.
Like my question is, what do you see in what? zzzcode.ai suggested opposite order should be by which is put first so that is wrong. I have heard this may depend on size, bigger is more likely to display, compatibility, favicon.ico at root of public_html is given if GIF is incompatible and there is no other, and order in HTML, later is more likely displayed. Tell me at maybejosiah@aol.com if I am wrong. Pages that are in this test now are this page, main gugquettex.com index.php, and gugquettex.com/en/blog/mors.html. favicon.ico is 246x246, favicon.png is 52x52, and icon.gif is 100x100.
So far Qwant search engine displays like my PNG for all pages including those without PNG image and so do some other search engines. Being named favicon has something toward being shown. Also according to Yandex having on home like gugquettex.com has an effect toward it being shown. I did try a Windows computer, all did not show animation and were varying from a static version of first frame of like my GIF to favicon.png. Without favicon.png on page they showed static first frame of icon.gif. Things that are not HTML or PHP always show favicon.ico. Static icon in Firefox on Ubuntu is favicon.png but favicon.gif is shown in top bar. This started near 6PM today and as of 8:10PM I am adding a second GIF before PNG so before and after PNG there is GIF.
9:21PM, results are that having a GIF link before and after a PNG maximizes chances of showing that GIF while some browsers still show PNG without being compatible. A note, Google Chrome on Windows 10 only showed GIF static start when GIF was all that was present. Everything except that Google Chrome either shows GIF animated, static start, or is incompatible which mostly shows PNG. Microsoft Bing does not show an image but does for others' icons so only having PNG or other not animated thing may be only way for that. Also, for things without an icon link, favicon.ico is best way to have an icon for that. 5/10/2024, 10:53AM, I am all in on this experiment with all pages.