id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
15930	Update opentopomap	jidanni	team	"We see
{{{
2018-02-16 08:59:22.042 INFO: GET http://tile.opentopomap.org/16/54767/28231.png -> 301 (341 B)
2018-02-16 08:59:22.042 INFO: Download redirected to 'https://tile.opentopomap.org/16/54767/28231.png'
}}}
And http is how it is listed on https://josm.openstreetmap.de/wiki/Maps too.

Looking at
https://opentopomap.org/about
we see it now also has a b c

{{{
<abbr title=""also z.B. http://a.tile.opentopomap.org/14/8695/5583.png"">{a|b|c}.tile.opentopomap.org/{z}/{x}/{y}.png</abbr>
}}}
(however the title should probably be https.)
"	enhancement	closed	normal		External imagery source		fixed