Comment # 2 on bug 1126566 from Andreas Stieger

(In reply to Tony Su from comment #0)
> Using Firefox 65.5.0esr 

No such version.

> The first noticeable error is that the website does not detect this brand
> new LEAP 15 correctly, offers Tumbleweed packages.

A website has zero business "detecting" your installation. The user may have
the last selected version saved in a cookie, this is a one-time operation. For
usability it would be better to get this cookie via a per-release landing URL.

Can you give the exact YML url used?