This is a format from a film lab subtitling. Film is expected to be subtitled in 35mm in feet.frame notation.
The file is a textfile with the following format. A first line "#title" which will be ignorerd. Then there is a line "in: Feet.Frames", one or two lines with text and a line "out: Feet.Frames". The out line can be zero, which means that the out-point is calculated automatically from the next inpoint. Subtitler uses the Split Distance in the Preferences to calculate the out-point.
in: 10.07 In this building behind me I spent over 70 nights and most days ... out 0.0 in: 16.12 during the war which lasted 77 days. out: 18.00