For installs on embedded devices running off of SD cards (ie Raspberry Pi), the partition layout appears to be a FAT boot partition that contains the kernel and system file system (SquashFS), and then the rest of the card is formatted with a large ext4 partition.
The downside of this is that if the SD card is then inserted into a Windows PC, only the small boot partition will be naively mounted - so you cannot copy over media files directly.
(Paragon has a free Windows program that works well for Windows to read/write ext4 but that is not very straightforward, and not a free option for OSX users.)
This feature request is for a "supported" method of resizing the ext4 partition to a large FAT32 partition; so on a 32 GB SD card for example:
~1GB - system/boot
~2GB - ext4 system extra space
~25GB - FAT32 user media space
Originally requested on downstream project Lakka: Feature request - allow SD card file transfer · Issue #125 · libretro/Lakka-LibreELEC · GitHub