'+' mark at the end of file attribute

drwxrwxr-x  30 aiden aiden      4096 Nov 24 22:18 tmp
drwxrwxr-x+ 30 aiden aiden      4096 Nov 25 00:30 aosp
-rw-r-----+  1 aiden aiden         0 Nov 25 14:39 1234.txt

像這樣，有些目錄/檔案，在 attrib 最後是 '+'

根據 + or @ after ls -al:
The + suffix means the file has an access control list, and is common in any *nix that supports ACLs. Giving ls the -e flag will make it show the associated ACLs after the file, and chmod can be used to modify then. Most of this is from the chmod man page: