Later when I saw this section again, I forgot why I split it...

There's an easy fix to that. Now that you've seen from AnomalousMonk's and ikegami's replies why

use constant {
    zed=>0,
    one=>1,
    two=>2,
};
use constant repos=>(qw(oss non-oss debug));
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was required rather than having repos defined in the same anonymous-hash, all you have to do is change that to

use constant {
    zed=>0,
    one=>1,
    two=>2,
};
use constant repos=>(qw(oss non-oss debug)); # NOTE to future self: ca
+nnot be in the `use constant { ... }`:
    # because an array cannot be the value for a key in an anonymous h
+ash; 
    # to create a constant array, it has to be in a separate `use cons
+tant` line; 
    # do not try to optimize this back into the `use constant {...}` b
+ecause it won't work!  
    # Really, I mean it!
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(though feel free to use your own commenting style)