This looks like Pseudo-Localization
That's pseudolocalization used to test compatibility across different languages. Microsoft and others have been doing it for years now.
During most development, the only language that has 100% coverage is en-us because 100% of primary development on Windows is done in Redmond.
Running non-US locales on insider builds, especially in Skip Ahead and Fast Ring, are only shipped with en-US and Pseudoloc'd locales. OP is definitely using en-UK ("programme") which means that a large number of strings are probably pseudoloc'd. This helps identify non-localized strings
it's weird enough that it won't make it into retail through an automated check (there's a lot of zero-width spaces in there, too, which aren't allowed in normal translations for the most part).
Strange font/characters in some apps
From the interface I can see that all characters are the direct analogs of the corresponding English character in the Greek alphabet. For example
- ΣΥΜ → SUM. Υ and Μ are upper case Upsilon and Mu, not Latin Y and M
- The options dialog has Δεϕαυλτ - Ενγλιση (ΥΣΑ) which transliterates to Default - English (USA). Similarly Εναβλεδ, Λοχαε → Enabled, Locale
- The menu reads Εδιτ ςιεω Ινσερτ Φορματ Τοολσ Δατα Ωινδοω Ηελπ which are simply Edit View Insert Format Tools Data Window Help transliterated
- And many more...
They're not Greek language at all, considering Tools menu in Greek is εργαλεία μενού that I can find even with zero knowledge of Greek language. Below is a menu in real Greek
There is another one who has exactly your problem when his French locale is translated letter-by-letter to Greek characters
In Libre Office a pseudo language called qtz is used while testing. I'm not sure about Open Office but I think the same thing happens. Probably you've used some beta or internal testing version, or the pseudo testing language was accidentally released which may be quickly solved by updating the application. Or try changing the interface language to another language and see if it displays correctly
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