strictures was never in core:

g:\Systeme\Regis-TR\XML>corelist strictures

strictures was not in CORE (or so I think)
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You should specify such prerequisites in your Makefile.PL (and from there, in your META.yml and META.json):

...
    PREREQ_PM => {
        strictures => 0,
    ...
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Debugging your list of prerequisites is always fun :)