The text for Mutual Favor, according to both the image of the card and the latest (presumably) official text in the NetrunnerDB entry the text of Mutual Favor is:
Search your stack for 1 icebreaker program and reveal it. (Shuffle your stack after searching it.) If you made a successful run this turn, you may install it. If you do not, add it to your grip.
The use of the ‘made’ (as opposed to ‘make’) indicates that a successful run needs to have happened, whereas the use of the word ‘do’ (as opposed to ‘did’) indicates that a successful run needs to happen but does not have to have happened yet. Which is it? Is there a typo? Am i misreading this?
Also, the play cost of Mutual Favor on the image of the card is 0 credits, whereas the play cost in the NetrunnerDB entry is X credits. 0 credits makes more sense given that there is no reference to what X refers to in the text of Mutual Favor.
I am not a rules expert.
This looks and works like the clause that we can see on Carmen or Marjanah, in a slightly different context.
You need to have made a successful run before (on the same turn) for you to be able to use the relevant part of this card’s ability.
As for the play cost, as of this writing it looks to me that both values are 0 credits.
I appreciate the reply Exile. I’ve asked about this on the Green Level Clearance Discord since posting this and so i think the credit error was corrected in response to that. I was misunderstanding the ‘If you do not’ as referring to a successful run rather than referring to installing.
I am a rules expert, and you and @Exile are correct that the “do” refers to the install.
English is not always easy to be perfectly clear and concise enough to fit on the textbox of a card. The “do” is the correct tense to refer back to the install. Which would also apply if you didn’t want to install or didn’t have the credits to pay for the install.
"Play for 0 credits. when you play this, search your stack for 1 icebreaker program and reveal it. (shuffle your stack after searching it.) if you successfully made a run earlier this turn, you may install it (you still pay the cost). if you didn’t make a successful run earlier this turn, you can’t install it. if you can’t install it, or don’t want to install it, add it to your grip.