About file names, ALM will use the same length for fully qualified names than the File System of Operative System which it's hosted, for Windows it's about 255 characters, for Linux it will depend, Here is some filename length limit in popular file systems:
ext2 -> 255 bytes
ext3 -> 255 bytes
ext3cow -> 255 bytes
ext4 -> 255 bytes
FAT32 -> 8.3 (255 UCS-2 code units with VFAT LFNs)[22]
NTFS -> 255 characters
A full list can be found here
https://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits
I tested the behavior in my lab and as long as the Server can handle the name of the file, it will be allowed in ALM, so hardcoded in ALM, there's no maximum value, that's the reason of the CR you found, the mentioned CR will include a feature to limit the length of the names as customer's desires, but for now, there's no limit, neither a recommended length.