/usr/share/lintian/overrides/libdb5.1-tcl is in libdb5.1-tcl 5.1.29-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | # historical reasons
libdb5.1-tcl: package-name-doesnt-match-sonames libdb-tcl-5.1
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