This avoids that we or users have to declare e.g. String or Uri in several places in Qt. This also prevents problems where multiple declarations (possibly from different headers) cause build errors. As a drive-by, remove some unnecessary type declarations (e.g. UriType, which had the same class string as Uri). To ease the submodule update process, define a preprocessor symbol that submodules can use to conditionally declare the type locally. Once the dependency update is through, the symbol can be removed and submodules can use the declaration from qjnitypes.h. Pick-to: 6.8 Change-Id: I7d96edf644a54246302b5c5cb478e66fa615e73e Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>