Because it was smaller than the FLAC option I presumed the ALAC was all 16/44.1 and the FLAC was all hi res. I downloaded both to see, and was wrong on both accounts.
The FLAC consists of this assortment of songs:
1) 24/96
8) 24/48
34) 24/44.1
44) 16/44.1
The ALAC consists of this assortment of songs:
9) 16/48
78) 16/44.1
So all of the 24-bit songs were converted to 16 bit and the lone 96kHz file got a power-of-two sample rate truncation. Fair enough.
It's worth noting the Lavf encoder (based on ffmpeg?) used to create the ALAC files was set to 0 compression, which means they could have all just been AIFF with "no" relative file size penalty. This was discovered by noticing the bit rates --- all 1411kbps for the 16/44.1s and 1535kbps for the 16/48s, same as if they'd been AIFFs. I took one of the supplied ALACs, made my own ALAC from it and the file size shrank to 1/3.


