These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.51 s (backtrack: 0/20).

[ebuild     U  ] app-text/doxygen-1.18.0-r1::gentoo [1.16.1::gentoo] USE="-clang -debug -doc -dot -doxysearch -gui -test" LLVM_SLOT="22* -18 -19 -20 -21*" 9674 KiB

Total: 1 package (1 upgrade), Size of downloads: 9674 KiB