In the recent time I encountered a lot of LO Writer crashes, e.g. with these builds:
 fc4f7db59152f606b6aa88cf32197700959d0f8b b76a3bdc996f275f9d615b32d6ab89d533a7505c f4c24da1e7f11664e0d2f688d2531f068e4a3bc0

Of course I let the system send automatic crash reports but I am concerned that frequent crashing still goes on.

In order to look into it, I deleted old crash reports in /var/crash/and all files from ~/.config/libreofficedev/4/user/uno_packages/cache and then I started libreofficedev7.6 (assuming that they will be created new, just to exclude inconsitencies from this source) from the command line. In order to exclude any problems from the big LO Writer documents I frequently work with, in this session I just opened a new file then I quit LO Writer without storing the just opened document. My terminal showed me these messages:

v@W:~$ rm -R /home/verwalter/.config/libreofficedev/4/user/uno_packages/cache
v@W:~$ libreofficedev7.6 
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:vcl:10555:10555:vcl/unx/gtk3/a11y/atklistener.cxx:176: index hint out of range, ignoring
warn:i18nlangtag:10555:10555:i18nlangtag/source/languagetag/languagetag.cxx:1435: LanguageTagImpl::convertLocaleToLang: with bAllowOnTheFlyID invalid 'de-AT-frami'
warn:i18nlangtag:10555:10555:i18nlangtag/source/languagetag/languagetag.cxx:1435: LanguageTagImpl::convertLocaleToLang: with bAllowOnTheFlyID invalid 'de-DE-frami'
warn:i18nlangtag:10555:10555:i18nlangtag/source/languagetag/languagetag.cxx:1435: LanguageTagImpl::convertLocaleToLang: with bAllowOnTheFlyID invalid 'de-CH-frami'
warn:linguistic:10555:10555:linguistic/source/lngprophelp.cxx:632: unknown property 'HyphNoLastWord'
warn:linguistic:10555:10555:linguistic/source/lngprophelp.cxx:632: unknown property 'HyphZone'
warn:sal.osl:10555:10555:sal/osl/unx/module.cxx:103: dlopen(/opt/libreofficedev7.6/program/libjava_gcc3.so, 257): /opt/libreofficedev7.6/program/libjava_gcc3.so: cannot open shared object file: No such file or directory
warn:sal.osl:10555:10555:sal/osl/unx/module.cxx:103: dlopen(/opt/libreofficedev7.6/program/libgcc3_java.so, 257): /opt/libreofficedev7.6/program/libgcc3_java.so: cannot open shared object file: No such file or directory
warn:legacy.tools:10555:10555:sfx2/source/control/bindings.cxx:1770: No cache for OfficeDispatch!
warn:vcl.layout:10555:10555:vcl/source/window/dockwin.cxx:1057: DockingWindow has become non-layout because extra children have been added directly to it.
warn:unotools.config:10555:10555:unotools/source/config/configmgr.cxx:147: ConfigManager not empty
v@W:~$

Do these messages give any clue what is going wrong? 
Or shall one just ignore them?

Working with the development version is quite frustrating at the moment for me. Of course I can use my parallel install LibreOffice 6.4.4.2, but then I can't alert you about issues in the development version.

Note: I have AltSearch 1.4.2 installed because I use it frequently. Is there anything pointing to it as the source of instability?