@AndyBrice
LLVM MinGW 17.0.6
C:\Projects\C++\TextEncodings\build\Desktop_Qt_6_10_0_llvm_mingw_64_bit-Debug\TextEncodings.exe...
"UTF-8"
"UTF-16"
"UTF-16LE"
"UTF-16BE"
"UTF-32"
"UTF-32LE"
"UTF-32BE"
"ISO-8859-1"
MinGW 13.1.0
C:\Projects\C++\TextEncodings\build\Desktop_Qt_6_10_0_MinGW_64_bit-Debug\TextEncodings.exe...
"UTF-8"
"UTF-16"
"UTF-16LE"
"UTF-16BE"
"UTF-32"
"UTF-32LE"
"UTF-32BE"
"ISO-8859-1"
MSVC 20222
C:\Projects\C++\TextEncodings\build\Desktop_Qt_6_10_0_MSVC2022_64bit-Debug\TextEncodings.exe...
"Locale"
"UTF-8"
"UTF-16"
"UTF-16BE"
"UTF-16LE"
"UTF-32"
"UTF-32BE"
"UTF-32LE"
"UTF16_PlatformEndian"
"UTF16_OppositeEndian"
"UTF32_PlatformEndian"
"UTF32_OppositeEndian"
"UTF-16BE,version=1"
"UTF-16LE,version=1"
"UTF-16,version=1"
"UTF-16,version=2"
"UTF-7"
"IMAP-mailbox-name"
"SCSU"
"BOCU-1"
"CESU-8"
"ISO-8859-1"
"US-ASCII"
"GB18030"
"ISO-8859-2"
"ISO-8859-3"
"ISO-8859-4"
"ISO-8859-5"
"ISO-8859-6"
"ISO-8859-7"
"ibm-813_P100-1995"
"ISO-8859-8"
"ibm-916_P100-1995"
"ISO-8859-9"
"ISO-8859-10"
"iso-8859_11-2001"
"ISO-8859-13"
"ISO-8859-14"
"ISO-8859-15"
"ibm-942_P12A-1999"
"Shift_JIS"
"ibm-943_P130-1999"
"ibm-33722_P12A_P12A-2009_U2"
"ibm-33722_P120-1999"
"ibm-954_P101-2007"
"EUC-JP"
"ibm-1373_P100-2002"
"Big5"
"ibm-950_P110-1999"
"Big5-HKSCS"
"ibm-5471_P100-2006"
"ibm-1386_P100-2001"
"GBK"
"GB2312"
"GB_2312-80"
"euc-tw-2014"
"ibm-964_P110-1999"
"ibm-949_P110-1999"
"ibm-949_P11A-1999"
"EUC-KR"
"ibm-971_P100-1995"
"cp1363"
"ibm-1363_P110-1997"
"KSC_5601"
"windows-874-2000"
"TIS-620"
"ibm-1162_P100-1999"
"IBM437"
"ibm-720_P100-1997"
"ibm-737_P100-1997"
"IBM775"
"IBM850"
"cp851"
"IBM852"
"IBM855"
"ibm-856_P100-1995"
"IBM857"
"IBM00858"
"IBM860"
"IBM861"
"IBM862"
"IBM863"
"IBM864"
"IBM865"
"IBM866"
"ibm-867_P100-1998"
"IBM868"
"IBM869"
"KOI8-R"
"ibm-901_P100-1999"
"ibm-902_P100-1999"
"ibm-922_P100-1999"
"KOI8-U"
"ibm-4909_P100-1999"
"windows-1250"
"windows-1251"
"windows-1252"
"windows-1253"
"windows-1254"
"windows-1255"
"windows-1256"
"windows-1257"
"windows-1258"
"ibm-1250_P100-1995"
"ibm-1251_P100-1995"
"ibm-1252_P100-2000"
"ibm-1253_P100-1995"
"ibm-1254_P100-1995"
"ibm-1255_P100-1995"
"ibm-5351_P100-1998"
"ibm-1256_P110-1997"
"ibm-5352_P100-1998"
"ibm-1257_P100-1995"
"ibm-5353_P100-1998"
"ibm-1258_P100-1997"
"macintosh"
"x-mac-greek"
"x-mac-cyrillic"
"x-mac-centraleurroman"
"x-mac-turkish"
"hp-roman8"
"Adobe-Standard-Encoding"
"ibm-1006_P100-1995"
"ibm-1098_P100-1995"
"ibm-1124_P100-1996"
"ibm-1125_P100-1997"
"ibm-1129_P100-1997"
"ibm-1131_P100-1997"
"ibm-1133_P100-1997"
"gsm-03.38-2009"
"ISO-2022-JP"
"ISO-2022-JP-1"
"ISO-2022-JP-2"
"ISO_2022,locale=ja,version=3"
"ISO_2022,locale=ja,version=4"
"ISO-2022-KR"
"ISO_2022,locale=ko,version=1"
"ISO-2022-CN"
"ISO-2022-CN-EXT"
"ISO_2022,locale=zh,version=2"
"HZ-GB-2312"
"x11-compound-text"
"ISCII,version=0"
"ISCII,version=1"
"ISCII,version=2"
"ISCII,version=3"
"ISCII,version=4"
"ISCII,version=5"
"ISCII,version=6"
"ISCII,version=7"
"ISCII,version=8"
"LMBCS-1"
"IBM037"
"IBM273"
"IBM277"
"IBM278"
"IBM280"
"IBM284"
"IBM285"
"IBM290"
"IBM297"
"IBM420"
"IBM424"
"IBM500"
"ibm-803_P100-1999"
"IBM-Thai"
"IBM870"
"IBM871"
"ibm-875_P100-1995"
"IBM918"
"ibm-930_P120-1999"
"ibm-933_P110-1995"
"ibm-935_P110-1999"
"ibm-937_P110-1999"
"ibm-939_P120-1999"
"ibm-1025_P100-1995"
"IBM1026"
"IBM1047"
"ibm-1097_P100-1995"
"ibm-1112_P100-1995"
"ibm-1122_P100-1999"
"ibm-1123_P100-1995"
"ibm-1130_P100-1997"
"ibm-1132_P100-1998"
"ibm-1137_P100-1999"
"ibm-4517_P100-2005"
"IBM01140"
"IBM01141"
"IBM01142"
"IBM01143"
"IBM01144"
"IBM01145"
"IBM01146"
"IBM01147"
"IBM01148"
"IBM01149"
"ibm-1153_P100-1999"
"ibm-1154_P100-1999"
"ibm-1155_P100-1999"
"ibm-1156_P100-1999"
"ibm-1157_P100-1999"
"ibm-1158_P100-1999"
"ibm-1160_P100-1999"
"ibm-1164_P100-1999"
"ibm-1364_P110-2007"
"ibm-1371_P100-1999"
"ibm-1388_P103-2001"
"ibm-1390_P110-2003"
"ibm-1399_P110-2003"
"ibm-5123_P100-1999"
"ibm-8482_P100-1999"
"ibm-16684_P110-2003"
"ibm-4899_P100-1998"
"ibm-4971_P100-1999"
"ibm-9067_X100-2005"
"ibm-12712_P100-1998"
"ibm-16804_X110-1999"
"ibm-37_P100-1995,swaplfnl"
"ibm-1047_P100-1995,swaplfnl"
"ibm-1140_P100-1997,swaplfnl"
"ibm-1141_P100-1997,swaplfnl"
"ibm-1142_P100-1997,swaplfnl"
"ibm-1143_P100-1997,swaplfnl"
"ibm-1144_P100-1997,swaplfnl"
"ibm-1145_P100-1997,swaplfnl"
"ibm-1146_P100-1997,swaplfnl"
"ibm-1147_P100-1997,swaplfnl"
"ibm-1148_P100-1997,swaplfnl"
"ibm-1149_P100-1997,swaplfnl"
"ibm-1153_P100-1999,swaplfnl"
"ibm-12712_P100-1998,swaplfnl"
"ibm-16804_X110-1999,swaplfnl"
"ebcdic-xml-us"
As suspected. MinGW is treated as a second class citizen ... 🤷🏻♂️
Edit: I've opened up https://bugreports.qt.io/browse/QTBUG-140865