SUMMARY

Kate and kwrite fail to digest certain legacy configuration and crash during startup.

STEPS TO REPRODUCE
1.  Insert specific config in your $HOME/.config/katevirc :

[Kate Vi Input Mode Settings]
Command Mode Mapping Keys=
Command Mode Mappings=
Command Mode Mappings Recursion=
Insert Mode Mapping Keys=
Insert Mode Mappings=
Insert Mode Mappings Recursion=
Macro Completions=
Macro Contents=
Macro Registers=
Map Leader=,
Normal Mode Mapping Keys=<c-v>,<s-insert>,v<left>w
Normal Mode Mappings="+gP,"+gP,vb
Normal Mode Mappings Recursion=false,false,false
ViRegisterContents=inconclusive,\t\t\t\t\t<p>\n\t\t\t\t\t\tIn contrast to previous evaluation\\, the evaluator determined that <b>no</b> additional packages that be acquired this time. The distribution DVDs are in fact self-contained. \n\t\t\t\t\t\t<!--are clearly identified in the <bibref>ECG</bibref> and a URL is given so that the administrator can find the additional packages on the SUSE FTP site. Sufficient instructions are given so that the administrator can reasonably be expected to find and download the correct additional packages. The evaluator found also that sufficient instructions are given so that the administrator can check the integrity of the downloaded packages using the instructions given.-->\n\t\t\t\t\t</p>\n,<dl>\n                     The extended components definition in ASE_ECD.\n                  </dl>\n                  <dt>\n                  </dt>\n                  <dl>\n                     The remaining\\, non-mandatory parts of the ST.\n                  </dl>\n                  <dt>\n                  </dt>\n               </ul>
ViRegisterFlags=0,1,0
ViRegisterNames=-,0,^
Visual Mode Mapping Keys=<s-c-a-m-><s->,<c-x>,<c-c>,<c-insert>
Visual Mode Mappings="+y,"+x,"+x,"+y
Visual Mode Mappings Recursion=false,false,false,false

2.  Run kate or kwrite
3.  Observe the crash

OBSERVED RESULT

The application crashes during startup.

Output of "strace kwrite" is:

readlink("/home", 0x7ffc14ffd8f0, 1023) = -1 EINVAL (Invalid argument)
readlink("~", 0x7ffc14ffd8f0, 1023) = -1 EINVAL (Invalid argument)
readlink("~/.config", 0x7ffc14ffd8f0, 1023) = -1 EINVAL (Invalid argument)
readlink("~/.config/katevirc", 0x7ffc14ffd8f0, 1023) = -1 EINVAL (Invalid argument)
openat(AT_FDCWD, "/home/andreas/.config/katevirc", O_RDONLY|O_CLOEXEC) = 19
statx(19, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_ALL, {stx_mask=STATX_ALL|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0600, stx_size=1666, ...}) = 0
statx(19, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_ALL, {stx_mask=STATX_ALL|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0600, stx_size=1666, ...}) = 0
statx(19, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_ALL, {stx_mask=STATX_ALL|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0600, stx_size=1666, ...}) = 0
read(19, "[Kate Vi Input Mode Settings]\nCo"..., 16384) = 1666
read(19, "", 14718)                     = 0
close(19)                               = 0
openat(AT_FDCWD, "/dev/tty", O_RDONLY|O_CLOEXEC) = 19
close(19)                               = 0
write(2, "ASSERT: \"rc <= 0xffff\" in file /"..., 89ASSERT: "rc <= 0xffff" in file /usr/include/x86_64-linux-gnu/qt6/QtCore/qchar.h, line 79
) = 89
rt_sigprocmask(SIG_UNBLOCK, [ABRT], NULL, 8) = 0
gettid()                                = 680280
getpid()                                = 680280
tgkill(680280, 680280, SIGABRT)         = 0
--- SIGABRT {si_signo=SIGABRT, si_code=SI_TKILL, si_pid=680280, si_uid=1001} ---
+++ killed by SIGABRT +++
Aborted

I do not get offered a debug option, therefore, no complete debug logs included.

EXPECTED RESULT

Kwrite and kate handle the apparently invalid config gracefully and startup normally.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE Neon user edition
KDE Plasma Version: 6.0.2
KDE Frameworks Version: Version 6.0.0
Qt Version: 6.6.2

ADDITIONAL INFORMATION

I upgraded from KDE Neon user edition where the config used to work.
It suffices to remove the line 
Visual Mode Mapping Keys=<s-c-a-m-><s->,<c-x>,<c-c>,<c-insert>
from above config.