Robert Leonhard wrote:
What does "-1 Attack vs. (#) Bomber" mean?
That really should say "-1 Attack vs. (#) Air to Air
What does "Strike Aircraft firing" mean? What is a Strike Aircraft?
During the Strike phase, if you intercept a Strike mission and manage to fire on an air unit which is designated as a strike air unit rather than an escort.
EDIT: I didn't actually answer the question. The DRM is for the strike aircraft firing.
What does "-1 Attack vs. (#) or 0 Air to Air Strength" mean?
Apply a -1 DRM to your roll when you attack an air units which has a parenthesized or 0 air to air rating.