Safari 9 Not Showing SVG Pinned Tab Icon

Question

I created a new pinned-tab icon for Safari 9 on El Capitan as documented by Apple here but I can't seem to get Safari to actually show it when I pin my tab.

Here's the line in my header:

<link rel="mask-icon" href="https://towatchlist.com/img/twl.svg" color="red"> 

Safari does show the image just fine when I follow the link to the SVG file, but the pinned tab icon still shows the auto-generated letter image even after reloads and pin/unpin etc.

I tried opening up GitHub's SVG (which is working) and copying the general markup there but that didn't fix things either. I also poked through the Safari console briefly but didn't see it even attempting to land the SVG file.

Any suggestions on how to even debug this or ideas on what is going wrong?

Answer 1

Looks like Safari is aggressively caching (even the absence of) these icons. Found the answer over on Super User:

Delete the contents of the following folder:

~/Library/Safari/Template Icons 

And then restart Safari.