I can open the schematic (using the cached symbols) The schematic looks plausible. Looking into the file it does indeed appear to be from KiCad V3 version. Footprint links in the schematic do not have a library name. This is also a very old convention. I think it means that KiCad just uses any footprint it finds with a matching name.
I can not open the PCB, The PCB crashes on attempting this. (Segmentation fault, core dumped) KiCad has proclaimed it should always be able to open older files, but I am not sure whether files this old are supported. Your project may be worth it to be used in a bug report if projects this old should work in KiCad, but that would require uploading to gitlab. Issues on gitlab can be made private.
The project has a (seemingly) complete set of gerber files. KiCad can reverse-create a PCB from Gerber files, but this process is not automatic. It also can not recover footprints, as footprints do not exist in Gerber files. More info about this path in: Reverse engineering KiCad project from Gerber files
After adding both the “-cache” and the “-rescue” libraries to a random project of mine, I can open these libraries and get symbols out of them. Maybe it’s worth saving a few symbols, but most are probably better replaced with standard symbols from a newer KiCad version.
How many of such projects do you have to sort out?
KiCad version used to read the project:
Application: KiCad Schematic Editor x86_64 on x86_64
Version: 8.0.4-8.0.4-0~ubuntu20.04.1, release build
Libraries:
wxWidgets 3.2.2
FreeType 2.10.1
HarfBuzz 2.6.4
FontConfig 2.13.1
libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3
Platform: Linux Mint 20.3, 64 bit, Little endian, wxGTK, X11, xfce, x11
OpenGL: AMD, AMD RENOIR (DRM 3.42.0, 5.15.0-117-generic, LLVM 12.0.0), 4.6 (Compatibility Profile) Mesa 21.2.6
Build Info:
Date: Jul 17 2024 01:37:21
wxWidgets: 3.2.1 (wchar_t,wx containers) GTK+ 3.24
Boost: 1.71.0
OCC: 7.6.3
Curl: 7.68.0
ngspice: 42
Compiler: GCC 9.4.0 with C++ ABI 1013
Build settings: