Hi @OdysLam , thank you very much for your reply and helpful investigation. Actually my question has been resolved with your help. Sorry for my long answer
Obviously, double //
is not a problem, that code was copied as is from Netdata alarms modal window:
I tried to play with embedding html because it show me a nice preview in my favorite markdown editor Typora. But after reading Gitlab documentaion I’ve made some commits to my local gitlab directly from IDE and found a solution:
Finally I use the second URL from active alarms’ modal window.
This badge appears in my readme.md file with the following code:
[Disk IO backlog](http://example.com:19999/#menu_disk_submenu_sda) 
Honestly, auto refresh doesn’t work right now) but I’m happy though disk performance is being degraded and everybody can see it when opens that readme))