I dug into the source. I can see where another guess at the path could be made or one of the existing 3 could be loosened up to match the output of Debian's clang-11 --version output.
Details: In KDevelop source: plugins/clang/duchain/clanghelpers.cpp QString ClangHelpers::clangVersion(){ ... QRegularExpression re(QStringLiteral("^clang version (\\d+\\.\\d+\\.\\d+)")); ... } The regular expression won't match as the Debian version of clang-11 has the line starting with 'Debian clang' instead of just 'clang' >clang-11 --version Debian clang version 11.0.1-2 Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/bin