SPDX report:

Main problem are several LGPL-2.0-only files that are combined with incompatible licenses.
Nice to have would be to relicense GPL (sic!) sources in library component to LGPL while working on this.

Reaming files in src:/
kioslaves/timeline/timelinetools.h:5: SPDX-License-Identifier: LGPL-2.0-only
file/fileexcludefilters.h:5: SPDX-License-Identifier: LGPL-2.0-only
file/priority.cpp:8: SPDX-License-Identifier: LGPL-2.0-only
file/metadatamover.cpp:6: SPDX-License-Identifier: LGPL-2.0-only
file/fileindexerconfig.cpp:7: SPDX-License-Identifier: LGPL-2.0-only
file/filewatch.h:5: SPDX-License-Identifier: LGPL-2.0-only
file/fileexcludefilters.cpp:5: SPDX-License-Identifier: LGPL-2.0-only
file/metadatamover.h:6: SPDX-License-Identifier: LGPL-2.0-only
file/fileindexerconfig.h:6: SPDX-License-Identifier: LGPL-2.0-only
file/powerstatemonitor.cpp:6: SPDX-License-Identifier: LGPL-2.0-only
file/priority.h:5: SPDX-License-Identifier: LGPL-2.0-only
file/filewatch.cpp:6: SPDX-License-Identifier: LGPL-2.0-only
file/powerstatemonitor.h:6: SPDX-License-Identifier: LGPL-2.0-only

MR for first set of simple conversions (all authors already in relicensingscript.pl): https://invent.kde.org/frameworks/baloo/-/merge_requests/8
src/file/fileexcludefilters.h
src/file/priority.cpp
src/file/priority.h

Remaining files after latest update (mails sent to remaining contributors for license changes):
file/metadatamover.cpp:6: SPDX-License-Identifier: LGPL-2.0-only
file/fileindexerconfig.cpp:7: SPDX-License-Identifier: LGPL-2.0-only
file/metadatamover.h:6: SPDX-License-Identifier: LGPL-2.0-only
file/fileindexerconfig.h:6: SPDX-License-Identifier: LGPL-2.0-only
file/powerstatemonitor.cpp:6: SPDX-License-Identifier: LGPL-2.0-only
file/filewatch.cpp:6: SPDX-License-Identifier: LGPL-2.0-only

Remaining ones for now, still hunting original contributors:
src/file/fileindexerconfig.cpp:7: SPDX-License-Identifier: LGPL-2.0-only
src/file/fileindexerconfig.h:6: SPDX-License-Identifier: LGPL-2.0-only