In Find and Replace dialog \l with regex should mean 'find any letter', it does not work but finds just literal l. Seen Writer, Calc, OO and LO 24.2. Workaround: use [a-zA-Z]
\l should not "find any letter", in fact \l isn't assigned any special metacharacter meaning, see https://unicode-org.github.io/icu/userguide/strings/regexp.html#regular-expression-metacharacters Any letter (not just ASCII) would be one of [\p{L}] or [\p{Letter}] or [\p{General_Category=Letter}] See https://unicode-org.github.io/icu/userguide/strings/regexp.html#set-expressions-character-classes Help doesn't mention such \l thing either, https://help.libreoffice.org/7.5/en-GB/text/shared/01/02100001.html Also POSIX Basic or Extended Regular Expressions don't know \l nor any of the other regex dialects I know, so I don't know where you got that, but it's a wrong expectation.
Thanks Eike. I saw \l in Alternative Search extension for Writer and it seemed so logical that I did not check more.
For the records, that seems to be this https://extensions.libreoffice.org/en/extensions/show/alternative-dialog-find-replace-for-writer