On Linux, an IPv6 address can have a scope ID at the end with a percent sign before it. For example:
fe80::1%usb0. See Why is there a percent sign '%' in the IPv6 address?
I want to add such an entry to my ssh config, but if I add
HostName fe80::1%usb0 to
~/.ssh/config, I get an error:
percent_expand: unknown key %u