By the way, as you may have seen in the search string I linked to above, the Swedish Wikivoyage had also implemented a <stay> tag, on top of the standard <buy>, <do>, <drink>, <eat>, <listing>, <see> and <sleep> ones. I've search for <stay> in the other language versions of Wikivoyage listed above (el, fi, fr, pl, pt, ro, ru, uk, zh) and as far as I can tell it's not used there. (Slight reservation for the Chinese, Russian and Ukrainian language versions since they don't use Latin script – however I guess their code strings should still be in English?)

I've now removed all instances of the Listings extension from the Swedish Wikivoyage: please see these sv.Voy query results: (buy|do|drink|eat|listing|see|sleep|stay).

For what it's worth, I can report that this problem doesn't replicate when using the Vector legacy (2010) appearance skin.

In T346513#9192997, @Aklapper wrote:

Where and how to see that exactly, after which steps performed? Could you provide a screenshot?
P52520 is access-restricted to you and me so this should not be displayed.

Hello again @Aklapper. Thank you so much for your help! So I guess I should simply add my secret user committed identity hash text string to P52520? Regardless of the fact that the page there says "Please be aware that whatever you paste here will be publicly visible for the world to see. Do not paste private or sensitive information"?

I agree with @Taylor's proposal. This needs to be fixed.