Reversed Engineered from Uniqueness (Cop's Thread)
Haskell, 173 bytes, 8 unique, 1384 points, safe

&quot;[tag:reverse_engineering]&quot;

It looks like this answer wants to provide a relevant tag to the question, while using only 8 different bytes.
As usual, your solution should work by being pasted in the code block on TIO: Try it online!

Solution
'[':___':_'':_':':':__':__:__'':__:__':____:__:'_':__:___:_':_'_:___:__:__:__':_'_:___:_':']':[]
_:_:_'':_:_:_:__:_:_':_:_'_:_:_:_:_:___:_:_:_:__':____:___':_:__'':_=['_'..]

Yes, this is valid Haskell code: Try it online!
How it works
The underscore _ is used as a wild card in Haskell's pattern matching. ' is used for characters, e.g. 'a'. However, both _ and ' are also part of the allowed characters for identifier names (Within some restrictions, e.g. ' cannot occur at the beginning of the name.). Therefore __, _', _'_, _'' and so on are all valid identifier names. Using some more descriptive names, the above code becomes
'[':t:a:g:':':r:e:v:e:r:s:e:'_':e:n:g:i:n:e:e:r:i:n:g:']':[]
_:_:a:_:_:_:e:_:g:_:i:_:_:_:_:n:_:_:_:r:s:t:_:v:_=['_'..]

The first line yields the string &quot;[tag:reverse_engineering]&quot; if each variable is assigned to the correct character. This assignment is achieved in the second line: ['_'..] yields the string &quot;_`abcdefghijklmnopqrstuvwxyz{|}~ ... &quot;, witch is matched on the pattern _:_:a:_:_:_:e:_:g:_:i:_:_:_:_:n:_:_:_:r:s:t:_:v:_ to get the desired assignment a='a', e='e' and so on.