Why would two bibliography entries display their title in different formats? For no apparent reason I get one title in double quotes and one title in italics .
This is in a \documentclass{book} I have a .bib collection with @techreport and @article entries.
Compiling with current versions LaTeX, LuaLaTeX or XeLaTeX biblatex and biber or BibTeX, so overall, I assume I overlook a fundamental difference in how these to reference classes are handled. Could someone point me to the right region?

biblatex. You may want to look into makingbiblatexsupport your language (https://tex.stackexchange.com/q/200932/35864) or switching the bibliography to a supported language. – moewe Jan 27 '22 at 16:27\babeland\csquotes. – Jona Engel Jan 28 '22 at 02:38