I just found out that the qtbase-opensource-src debian package regenerates src/corelib/io/qurltlds_p.h at build time from /usr/share/publicsuffix/effective_tld_names.dat, which is provided by the publicsuffix package.
Looking at the contents of /usr/include/x86_64-linux-gnu/qt5/QtCore/5.5.1/QtCore/private/qurltlds_p.h (provided by qtbase5-private-dev), they widely differ from the version in the source tree, and indeed the "com" suffix isn’t in there, so that file is clearly corrupted.
I just found out that the qtbase- opensource- src debian package regenerates src/corelib/ io/qurltlds_ p.h at build time from /usr/share/ publicsuffix/ effective_ tld_names. dat, which is provided by the publicsuffix package.
Looking at the contents of /usr/include/ x86_64- linux-gnu/ qt5/QtCore/ 5.5.1/QtCore/ private/ qurltlds_ p.h (provided by qtbase5- private- dev), they widely differ from the version in the source tree, and indeed the "com" suffix isn’t in there, so that file is clearly corrupted.