Javier Mora [off-list ref] writes:
This results in an ambiguous case, and Git does nothing to prevent it!
The documentation says that the longest insteadOf value wins, but both
have the same length since both are the same URL.
The longest has this case in mind:
[url "A"] insteadof = https://example.com/
[url "B"] insteadof = https://example.com/special/
So "A" is used as a replacement for the whole site, except for the
special hierarchy that is rewritten to "B".
Getting rid of what you no longer need with "config --unset" is the
right thing to do, and you did fine in the previous example.