@Mabbo Imocho, short for basically Saikin, imouto no yousu ga chotto okashiinda ga/Lately, my sister has been strange https://mangadex.org/title/3385/saikin-imouto-no-yousu-ga-chotto-okashiinda-ga
actually it even says in the chapter title after the move to the april fools collection, MD mods did a good job
I called the chapter initially something like "Jealous Imouto Bath Scene / Part 2 DLC locked"