When trying to bind > to a command, as in
> = :save<space>
aerc does not launch, printing
Failed to load config: Found '>' without '<'
">" also fails with the same message.
This comes from this section in config/bindings.go.
Removing that case from the switch seems to fix the issue, but I don't know if there is any other problem that that this switch is supposed to address, except for catching malformed bindings.