LDraw.org Official Parts Library Specifications

[Philippe Hurbain]

There is a slight ambiguity here:

Filenames must not be longer than 25 characters (including the extension) and must only contain the following characters:
a-z, 0-9, _,-

Is the . before extension included or not in the 25 characters? And obviously that . is allowed only for extension marking.
Since the extension is .dat anyway we could factor it out...

Overlapping and Intersecting Line Types

For clarity purpose, it might be interesting to mention that edge overlapping a primitive condline is alliowed, as well as condline overlapping a primitive condline on the end ("complementary condline)

These parts are typically modelled as a series of discrete part pieces that are then "formed" to simulate curvature. This places them in the shortcut category, and their descriptions will follow the rules outlined for shortcuts (i.e. use of the "~" character).

Flexible part fall into "shortcuts with moving parts" so generally the segment parts shouldn't use the "~" character.