It seems you can even assign namespaced sub names to *__ANON__ and have it work:

$ perl <<EOF
package Foo::Bar;
print sub { local *__ANON__ = "boo"; (caller(0))[3] }->();
EOF
Foo::Bar::boo

$ perl <<EOF
package Foo::Bar;
print sub { local *__ANON__ = "Foo::Zip::boo"; (caller(0))[3] }->();
EOF
Foo::Zip::boo
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