Sometimes you need to create a variable which can be accessed from outside the current package. That's what "our" is for.

package Foo;

my bar;
# Nobody outside of package Foo can access bar.

our baz;
# Anyone can access baz by referring to it as Foo::baz, no
# matter what package they're in (provided they use/require
# Foo).
#
# This also allows Foo to export baz, in which case other
# packages could import it and refer to it as just "baz".
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