xls & co. (the older ones) are something custom. Only after standardization as OOXML (a shitshow btw, there’s a lengthy wiki article about it) they got zip.
The whole Word and Libre/OO-Writer world is a shit show.
So complex and everyone decides to interpret it a bit differently.
Not even Libre and OO can be interoperabel between the same file and feature.
xls & co. (the older ones) are something custom. Only after standardization as OOXML (a shitshow btw, there’s a lengthy wiki article about it) they got zip.
The whole Word and Libre/OO-Writer world is a shit show.
So complex and everyone decides to interpret it a bit differently.
Not even Libre and OO can be interoperabel between the same file and feature.