What is this U folder under root /? I found this folder under my root, not sure what it is. Anyone got an idea?

drwx------    5 root  wheel    160 May  5  2017 casper
drwx------    3 root  wheel     96 May  5  2017 dists
drwx------    3 root  wheel     96 May  5  2017 install
drwx------  281 root  wheel   8992 May  5  2017 isolinux
-rw-r--r--    1 root  wheel  21744 Apr 12  2017 md5sum.txt
-rw-r--r--    1 root  wheel  60928 May  5  2017 menu.c32
drwx------   12 root  wheel    384 May  5  2017 pics
drwx------    4 root  wheel    128 May  5  2017 pool
drwx------    5 root  wheel    160 May  5  2017 preseed
-rw-r--r--    1 root  wheel   1707 May  5  2017 syslinux.cfg
-rw-r--r--    1 root  wheel  15097 May  5  2017 ubnfilel.txt
Catalina creates a read-only volume for System files, including the root level. You can't write to root level while booting from that volume. 

Normally, when Catalina is installed, the installer moves any third-party or user folders away from root level. It's not clear why that hasn't happened, unless the datestamp is not accurate. 


Disable SIP: Recovery mode, Terminal: csrutil disable
Restart.
Mount drive for read and write sudo mount -uw /  
Delete it [sudo] rm -rf /your\ folder\
Restart.
Enable SIP: Recovery mode, Terminal: csrutil enable