Computer program contains everything that's secret in General Election (6)
'that's secret in general election' is the definition.
'computer program contains everything' is the wordplay.
'computer program' becomes 'bot'.
'contains' is an insertion indicator.
'everything' becomes 'all' (I've seen this before).
'bot' placed around 'all' is 'BALLOT'.
(Other definitions for ballot that I've seen before include "Document listing the alternatives to vote for", "The process of exercising 20 Down", "Voting procedure", "Voting paper", "Plebiscite".)