In the early parts of Firewatch, Delilah receives a call from someone else. She tells you to hold on, but conspicuously leaves your frequency open. You can then overhear her side of the conversation she's having:
- Heyo. I don't think so. Why, have you?
- [annoyed] Okay, good.
- No, I don't think he has any idea.
- I'm absolutely sure.
- Would you?
- Alright. I'll let you know if anything changes in that regard.
If you immediately call her out on it, she gets annoyed and stops talking to you. Later on, when things start to get spooky, you can mention the conversation again as an example of the lines being bugged. Here, she brushes off your concern saying she just left the line open.
In my play through, that seemed to be the extent of that plot thread. Is there additional dialogue that I may have missed that resolves who Delilah was talking to, and why she seems to imply you're in the dark about something?