Appears to cause a crash since Firefox 76:
```
(lldb) bt
* thread #1, name = 'firefox', stop reason = signal SIGSEGV: invalid address (fault address: 0x0)
* frame #0: 0x0000000808006c1d libxul.so`mozilla::dom::ipc::SharedStringMap::SharedStringMap(mozilla::dom::ipc::SharedStringMapBuilder&&) + 93
frame #1: 0x0000000805efebbb libxul.so`(anonymous namespace)::SharedStringBundle::LoadProperties() + 971
frame #2: 0x0000000805efedde libxul.so`(anonymous namespace)::SharedStringBundle::GetStringImpl(nsTSubstring<char> const&, nsTSubstring<char16_t>&) + 46
frame #3: 0x0000000805efbbfb libxul.so`nsStringBundleBase::GetStringFromName(char const*, nsTSubstring<char16_t>&) + 123
frame #4: 0x000000080829a99d libxul.so`mozilla::widget::WidgetUtils::GetBrandShortName(nsTSubstring<char16_t>&) + 109
frame #5: 0x00000008082f1b79 libxul.so`nsAppShell::Init() + 473
frame #6: 0x0000000808318a76 libxul.so`nsWidgetGtk2ModuleCtor() + 102
frame #7: 0x0000000805e25f28 libxul.so`mozilla::xpcom::CreateInstanceImpl(mozilla::xpcom::ModuleID, nsISupports*, nsID const&, void**) + 7672
frame #8: 0x0000000805e34620 libxul.so`nsComponentManagerImpl::GetServiceLocked((anonymous namespace)::MutexLock&, (anonymous namespace)::EntryWrapper&, nsID const&, void**) + 704
frame #9: 0x0000000805e30d27 libxul.so`nsComponentManagerImpl::GetService(nsID const&, nsID const&, void**) + 151
frame #10: 0x0000000805e36887 libxul.so`nsGetServiceByCIDWithError::operator()(nsID const&, void**) const + 39
frame #11: 0x0000000805dc111e libxul.so`nsCOMPtr_base::assign_from_gs_cid_with_error(nsGetServiceByCIDWithError const&, nsID const&) + 46
frame #12: 0x00000008090b6455 libxul.so`nsAppStartup::Init() + 69
frame #13: 0x0000000805e25487 libxul.so`mozilla::xpcom::CreateInstanceImpl(mozilla::xpcom::ModuleID, nsISupports*, nsID const&, void**) + 4951
frame #14: 0x0000000805e34620 libxul.so`nsComponentManagerImpl::GetServiceLocked((anonymous namespace)::MutexLock&, (anonymous namespace)::EntryWrapper&, nsID const&, void**) + 704
frame #15: 0x0000000805e349a0 libxul.so`nsComponentManagerImpl::GetService(mozilla::xpcom::ModuleID, nsID const&, void**) + 352
frame #16: 0x0000000805e2bd9f libxul.so`mozilla::xpcom::GetServiceHelper::operator()(nsID const&, void**) const + 31
frame #17: 0x0000000805dc131e libxul.so`nsCOMPtr_base::assign_from_helper(nsCOMPtr_helper const&, nsID const&) + 46
frame #18: 0x0000000809161d43 libxul.so`ScopedXPCOMStartup::SetWindowCreator(nsINativeAppSupport*) + 99
frame #19: 0x000000080916739d libxul.so`XREMain::XRE_mainRun() + 45
frame #20: 0x0000000809168451 libxul.so`XREMain::XRE_main(int, char**, mozilla::BootstrapConfig const&) + 993
frame #21: 0x000000080916876e libxul.so`XRE_main(int, char**, mozilla::BootstrapConfig const&) + 174
frame #22: 0x0000000001030469 firefox`main + 585
frame #23: 0x000000000102ff55 firefox`_start(ap=<unavailable>, cleanup=<unavailable>) at crt1.c:76:7
```
Bug 1550891 Comment 7 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
**EDIT**: needs rebase to avoid accidentally omitting `ro_file = mapped_file_;`
Appears to cause a crash since Firefox 76:
```
(lldb) bt
* thread #1, name = 'firefox', stop reason = signal SIGSEGV: invalid address (fault address: 0x0)
* frame #0: 0x0000000808006c1d libxul.so`mozilla::dom::ipc::SharedStringMap::SharedStringMap(mozilla::dom::ipc::SharedStringMapBuilder&&) + 93
frame #1: 0x0000000805efebbb libxul.so`(anonymous namespace)::SharedStringBundle::LoadProperties() + 971
frame #2: 0x0000000805efedde libxul.so`(anonymous namespace)::SharedStringBundle::GetStringImpl(nsTSubstring<char> const&, nsTSubstring<char16_t>&) + 46
frame #3: 0x0000000805efbbfb libxul.so`nsStringBundleBase::GetStringFromName(char const*, nsTSubstring<char16_t>&) + 123
frame #4: 0x000000080829a99d libxul.so`mozilla::widget::WidgetUtils::GetBrandShortName(nsTSubstring<char16_t>&) + 109
frame #5: 0x00000008082f1b79 libxul.so`nsAppShell::Init() + 473
frame #6: 0x0000000808318a76 libxul.so`nsWidgetGtk2ModuleCtor() + 102
frame #7: 0x0000000805e25f28 libxul.so`mozilla::xpcom::CreateInstanceImpl(mozilla::xpcom::ModuleID, nsISupports*, nsID const&, void**) + 7672
frame #8: 0x0000000805e34620 libxul.so`nsComponentManagerImpl::GetServiceLocked((anonymous namespace)::MutexLock&, (anonymous namespace)::EntryWrapper&, nsID const&, void**) + 704
frame #9: 0x0000000805e30d27 libxul.so`nsComponentManagerImpl::GetService(nsID const&, nsID const&, void**) + 151
frame #10: 0x0000000805e36887 libxul.so`nsGetServiceByCIDWithError::operator()(nsID const&, void**) const + 39
frame #11: 0x0000000805dc111e libxul.so`nsCOMPtr_base::assign_from_gs_cid_with_error(nsGetServiceByCIDWithError const&, nsID const&) + 46
frame #12: 0x00000008090b6455 libxul.so`nsAppStartup::Init() + 69
frame #13: 0x0000000805e25487 libxul.so`mozilla::xpcom::CreateInstanceImpl(mozilla::xpcom::ModuleID, nsISupports*, nsID const&, void**) + 4951
frame #14: 0x0000000805e34620 libxul.so`nsComponentManagerImpl::GetServiceLocked((anonymous namespace)::MutexLock&, (anonymous namespace)::EntryWrapper&, nsID const&, void**) + 704
frame #15: 0x0000000805e349a0 libxul.so`nsComponentManagerImpl::GetService(mozilla::xpcom::ModuleID, nsID const&, void**) + 352
frame #16: 0x0000000805e2bd9f libxul.so`mozilla::xpcom::GetServiceHelper::operator()(nsID const&, void**) const + 31
frame #17: 0x0000000805dc131e libxul.so`nsCOMPtr_base::assign_from_helper(nsCOMPtr_helper const&, nsID const&) + 46
frame #18: 0x0000000809161d43 libxul.so`ScopedXPCOMStartup::SetWindowCreator(nsINativeAppSupport*) + 99
frame #19: 0x000000080916739d libxul.so`XREMain::XRE_mainRun() + 45
frame #20: 0x0000000809168451 libxul.so`XREMain::XRE_main(int, char**, mozilla::BootstrapConfig const&) + 993
frame #21: 0x000000080916876e libxul.so`XRE_main(int, char**, mozilla::BootstrapConfig const&) + 174
frame #22: 0x0000000001030469 firefox`main + 585
frame #23: 0x000000000102ff55 firefox`_start(ap=<unavailable>, cleanup=<unavailable>) at crt1.c:76:7
```