Looks like a DFHack issue. Here is the crashlog:
0> Dwarf_Fortress!std::_Init_locks::operator=+0x7F2B96
1> Dwarf_Fortress!std::_Init_locks::operator=+0x7F2D09
2> KERNELBASE!UnhandledExceptionFilter+0x1E7
3> ntdll!memset+0x13B0
4> ntdll!_C_specific_handler+0x96
5> ntdll!_chkstk+0x11F
6> ntdll!RtlRaiseException+0x484
7> ntdll!KiUserExceptionDispatcher+0x2E
8> dfhooks!DFHack::ptr_container_identity::lua_item_read+0x56
9> dfhooks!df::stl_string_identity::lua_write+0xFD1
10> lua!lua_setlocal+0xA3C
11> lua!luaopen_utf8+0x2478
12> lua!lua_setlocal+0x3B4
13> lua!luaopen_utf8+0x294B
14> lua!lua_yieldk+0x332
15> lua!lua_yieldk+0x1AD
16> lua!lua_setlocal+0xDF6
17> lua!lua_resume+0x139
18> dfhooks!DFHack::Screen::Painter::pen+0x235
19> dfhooks!df::stl_string_identity::lua_write+0x2601
20> lua!lua_setlocal+0xA3C
21> lua!luaopen_utf8+0x2421
22> lua!lua_setlocal+0x43B
23> lua!lua_callk+0x7C
24> dfhooks!DFHack::MaterialInfo::decode+0x2A6
25> lua!lua_setlocal+0xA3C
26> lua!lua_setlocal+0x42F
27> lua!lua_setlocal+0xDF6
28> lua!lua_setlocal+0x6B0
29> lua!lua_pcallk+0x10C
30> dfhooks!DFHack::Lua::SafeCall+0xCE
31> dfhooks!DFHack::Screen::Painter::pen+0x3E0
32> dfhooks!DFHack::Screen::Painter::newline+0x26A
33> dfhooks!DFHack::Core::doUpdate+0x34E
34> dfhooks!DFHack::Core::Update+0x75
35> Dwarf_Fortress!std::_Init_locks::operator=+0x626563
36> Dwarf_Fortress!std::_Init_locks::operator=+0x6278B9
37> SDL2!SDL_DYNAPI_entry+0x799D7
38> SDL2!SDL_DYNAPI_entry+0x12EEDE
39> ucrtbase!configthreadlocale+0x92
40> KERNEL32!BaseThreadInitThunk+0x14
41> ntdll!RtlUserThreadStart+0x21
The Legends Browser issue has been clarified, it tries to load _plus file for whatever reason.
After having transferred the save to another computer (still Windows), I have a crashlog:
0> Dwarf_Fortress!std::_Init_locks::operator=+0x7F2B96
1> Dwarf_Fortress!std::_Init_locks::operator=+0x7F2D09
2> KERNELBASE!UnhandledExceptionFilter+0x1E7
3> ntdll!memset+0x13B0
4> ntdll!_C_specific_handler+0x96
5> ntdll!_chkstk+0x11F
6> ntdll!RtlRaiseException+0x484
7> ntdll!KiUserExceptionDispatcher+0x2E
8> Dwarf_Fortress!std::_Init_locks::operator=+0xD71072
9> Dwarf_Fortress!std::_Init_locks::operator=+0xABD7AA
10> Dwarf_Fortress!std::_Init_locks::operator=+0x5F9ABC
11> overlay_plug+0x7F5E
12> Dwarf_Fortress!std::_Init_locks::operator=+0x8FA0D6
13> Dwarf_Fortress!std::_Init_locks::operator=+0x626504
14> Dwarf_Fortress!std::_Init_locks::operator=+0x6278B9
15> SDL2!SDL_DYNAPI_entry+0x799D7
16> SDL2!SDL_DYNAPI_entry+0x12EEDE
17> ucrtbase!configthreadlocale+0x92
18> KERNEL32!BaseThreadInitThunk+0x14
19> ntdll!RtlUserThreadStart+0x21