Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
gtkmm4.0-devel
gtkmm4.0-devel(x86-64)
pkgconfig(gtkmm-4.0)

Requires :

/usr/bin/pkg-config
gtkmm4.0(x86-64) = 4.17.0-1.fc42
libgtkmm-4.0.so.0()(64bit)
pkgconfig(cairomm-1.16) >= 1.15.4
pkgconfig(gdk-pixbuf-2.0) >= 2.35.5
pkgconfig(giomm-2.68) >= 2.75.0
pkgconfig(gtk4) >= 4.17.3
pkgconfig(gtk4-unix-print)
pkgconfig(pangomm-2.48) >= 2.50.0
pkgconfig(vulkan)
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rpmlib(PayloadIsZstd) <= 5.4.18-1

Content of RPM :
/usr/include/gtkmm-4.0
/usr/include/gtkmm-4.0/gdkmm
/usr/include/gtkmm-4.0/gdkmm.h
/usr/include/gtkmm-4.0/gdkmm/applaunchcontext.h
/usr/include/gtkmm-4.0/gdkmm/cairocontext.h
/usr/include/gtkmm-4.0/gdkmm/cairoutils.h
/usr/include/gtkmm-4.0/gdkmm/cicpparams.h
/usr/include/gtkmm-4.0/gdkmm/clipboard.h
/usr/include/gtkmm-4.0/gdkmm/colorstate.h
/usr/include/gtkmm-4.0/gdkmm/contentformats.h
/usr/include/gtkmm-4.0/gdkmm/contentformatsbuilder.h
/usr/include/gtkmm-4.0/gdkmm/contentprovider.h
/usr/include/gtkmm-4.0/gdkmm/cursor.h
/usr/include/gtkmm-4.0/gdkmm/device.h
/usr/include/gtkmm-4.0/gdkmm/devicepad.h
/usr/include/gtkmm-4.0/gdkmm/devicetool.h
/usr/include/gtkmm-4.0/gdkmm/devicewithpad.h
/usr/include/gtkmm-4.0/gdkmm/display.h
/usr/include/gtkmm-4.0/gdkmm/displaymanager.h
/usr/include/gtkmm-4.0/gdkmm/dmabufformats.h
/usr/include/gtkmm-4.0/gdkmm/dmabuftexture.h
/usr/include/gtkmm-4.0/gdkmm/dmabuftexturebuilder.h
/usr/include/gtkmm-4.0/gdkmm/drag.h
/usr/include/gtkmm-4.0/gdkmm/dragsurface.h
/usr/include/gtkmm-4.0/gdkmm/dragsurfaceimpl.h
/usr/include/gtkmm-4.0/gdkmm/dragsurfacesize.h
/usr/include/gtkmm-4.0/gdkmm/drawcontext.h
/usr/include/gtkmm-4.0/gdkmm/drop.h
/usr/include/gtkmm-4.0/gdkmm/enums.h
/usr/include/gtkmm-4.0/gdkmm/event.h
There is 670 files more in these RPM.