I have an sd card that used to be in an android phone.
My usua tools tell me very littls:

root@midwinter:~# lsblk --fs /dev/sdb
NAME   FSTYPE LABEL UUID MOUNTPOINT
sdb                      
├─sdb1                   
└─sdb2                   
root@midwinter:~# fdisk -l /dev/sdb
Disk /dev/sdb: 14.9 GiB, 15931539456 bytes, 31116288 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 4F1502F0-81F3-49FA-A294-8B8FB4DB6964

Device     Start      End  Sectors  Size Type
/dev/sdb1   2048    34815    32768   16M unknown
/dev/sdb2  34816 31116254 31081439 14.8G unknown
root@midwinter:~# 

Is there another way to find out anything? Or is this likely
to be an Google-encrypted card I can do nothing with except
restore it to an almost virginal state?

And what is the proper way to reformat an sdcard to the file
systems just about everything accepts without using
up its remaining lifetime?

-- hendrik