As per @NickD's comment, here is the help information for the o character in the file name:
position: 898 of 983 (91%), column: 3 character: o (displayed as o) (codepoint 111, #o157, #x6f) charset: ascii (ASCII (ISO646 IRV)) code point in charset: 0x6F script: latin syntax: w which means: word category: .:Base, L:Strong L2R, a:ASCII, l:Latin, r:Roman to input: type "C-x 8 RET 6f" or "C-x 8 RET LATIN SMALL LETTER O" buffer code: #x6F file code: #x6F (encoded by coding system utf-8) display: by this font (glyph code): mac-ct:-*-Ubuntu Mono-medium-normal-normal-*-20-*-*-*-m-0-iso10646-1 (#x52) And here is the ö character inside a file:
position: 101 of 13753 (1%), column: 0 character: ö (displayed as ö) (codepoint 246, #o366, #xf6) charset: unicode (Unicode (ISO10646)) code point in charset: 0xF6 script: latin syntax: w which means: word category: .:Base, L:Strong L2R, j:Japanese, l:Latin to input: type "C-x 8 RET f6" or "C-x 8 RET LATIN SMALL LETTER O WITH DIAERESIS" buffer code: #xC3 #xB6 file code: #xC3 #xB6 (encoded by coding system utf-8-unix) display: by this font (glyph code): mac-ct:-*-Ubuntu Mono-medium-normal-normal-*-20-*-*-*-m-0-iso10646-1 (#xD1) 