It had never occurred to me to use the automatic quoting of barewords before the fat comma for anything other than a hash key. Apparently it works in the even-numbered list positions as well, but I find this usage confusing.

Given this power of the fat comma, you could write

use strict;
my @days = (Mon=>Tue=>Wed=>Thu=>Fri=>);
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The fat comma is recommended for use in natural pairs, mostly the key-value pairs of a hash, and the option to omit the quotes around the hash keys is widely thought to improve the presentation.

Update: I stand corrected by the response below. Given that the post() parameters are not pairs, the following equivalent code would be standard formatting:

$kernel->post(
    ua           => 'request',
    got_response => GET $url,
);
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$kernel->post(
    'ua',
    'request',
    'got_response',
    GET $url,
);
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