How to display elements not readable by everyone (Linux, terminal)?

Question

linux

Can you please tell me how to find in the /etc folder all the elements that are not readable by everyone? I know that after the type there are 3 groups of characters that allow any action to be taken by the owner, group or other users. And what symbols indicate the prohibition of reading?
- (rw-) (rw-) (r--) 1 user user
type owner group others
(type) (owner) (group) (others)
I think grep can find unreadable elements, but I don't know how to specify /etc $ ls -l | grep...

Answer 1

The absence of bits is a prohibition:
- (rw-) (rw-) (r--)
Means that the owner can write / read, the group can write / read, everyone else can only read. Here, if rights are not explicitly set, then they are not.

Answer 2

find . -type f ! -perm /007
- display in the current directory all files that have access for others is empty (i.e. xx0 mode)