>it loads before other more standard fonts, and I often get an Acaill glyph (say in a Wikipedia article)

Which browsers and OS are you seeing this behavior? Sort order seems a strange way for font fallback to work.

Mac OS, various browsers. The characters in question are rare, and recently encoded, and are not part of any shipping core fonts. So the OS has to find a glyph to display them with, and it polls the installed fonts in alphabetical order until it finds one.

How else should the OS find a glyph that's not in the core or fallback fonts?

I renamed Walbaum News to Walburn (a made-up name), for several reasons.
Firstly, the name field was getting a bit crowded when "Display Bold italic" was added.
Secondly, I wasn't comfortable that it was a genuine Walbaum, considering the liberties I'd taken with it.
Thirdly, there were quite a few other Walbaums out there.

The original Beaufort was renamed Beaufort Old Style when I released the new, improved version.
Then I withdrew it.

>How else should the OS find a glyph that's not in the core or fallback fonts?

I suppose if it doesn't know about the code point then alphabetic order is understandable, but maybe should take panose values into account to say pick a font similar in design to the CSS "sans-serif" default (in the case of wikipedia).

Si

You could rename it EVRTP Acaill ;-)
Just joking, I don’t really like the various foundries’ suffixes. But I see plenty of renamed fonts, for one reason or another (sure yours is a peculiar one ;-)
One that comes to mind is Yanone Kaffeesats, renamed Kava when it went “pro“.

I'll probably rename it Dumha Goirt, then.

You should also make a font called Aaaarghversion that's a pirate version (hence the name) of the Mac OS default CSS sans font that includes the obscure codepoints.