Guys, if we look at the release of the latest cuda_10.2.89_mac.dmg, we see the following:
<key>NVDAResmanVersions</key>
<dict>
<key>378.10.10.10.15</key>
<string>378.10.10.10.15</string>
<key>378.10.10.10.20</key>
<string>378.10.10.10.20</string>
<key>378.10.10.10.25</key>
<string>378.10.10.10.25</string>
<key>387.10.10.10</key>
<string>387.10.10.10</string>
<key>387.10.10.15</key>
<string>387.10.10.15</string>
<key>418.15.10</key>
<string>418.15.10</string>
<key>418.20.10</key>
<string>418.20.10</string>
</dict>
And also these files:
libcuda_418.15.10_mercury.dylib
libcuda_418.20.10_mercury.dylib
So not only there is that 418.15.10 we never figured out where to get, now there is also a 418.20.10...
Edit: Looking further into the binaries I see references that these belong to a r440:
/dvs/p4/build/sw/rel/gpu_drv/r440/r440_00/drivers/gpgpu/_out/macosx_amd64_release/418.20.10_mercury/cudbgprocess.o
So where do we get these?