There seems to be no good way to handle non-general flat-footed conditions
Lets say for example I'm a Mastermind racket Rouge, and successfully identify a creature, then the target would be flat-footed for me until the start of my next turn (or 1 minute if critical success).
Currently for the Rouge it is possible to use the toggle "Enable abilities that require a flat-footed target", which effects things like Sneak Attack damage dice, but this doesn't work to enable the AC -2 penalty to the DC on the attack roll.
I'm not exactly sure what the best way would be to handle this, though. Maybe some character specific effect item, very similar to the flat-footed condition, but with a predicate to make it only valid for attacks from a single character ID. But I don't think it's currently possible to do this with predicates, and also I see no existing way to generate character-specific effects. Of course it would be possible to hard-code this and link it to the 'target:condition:flat-footed', but I guess that would not be preferred.
When we have conditional visibility then this would be a logical extension.
For now, that's up to the GM and player.