Swiss legend possibly revealing secrets (8)
I believe the answer is:
telltale
'revealing secrets' is the definition.
'telltale' can be an answer for 'revealing' (I've seen this before). I am not sure about the 'secrets' bit.
'swiss legend' is the wordplay.
'swiss' becomes 'tell' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'legend' becomes 'tale' (I've seen this in other clues).
'tell'+'tale'='TELLTALE'
'possibly' acts as a link.
Can you help me to learn more?
(Other definitions for telltale that I've seen before include "Revealer of secrets" , "Betraying" , "Revealing or indicating something, like blabbermouth" , "Person who blabs or something that reveals" , "Revealing indicator or sneak" .)