The file "include/owl/owlapp.rc" used to contain the default icons for OWL applications (IDI_OWLAPP and IDI_OWLAPPSM), but the icons were commented out before the release of 6.30 [r282], leaving the file without any resources at all (and hence useless). The reason for the change is not documented.
This issue was fixed in [r2760].
Related
Commit: [r2760]
Last edit: Vidar Hasfjord 2014-11-07
The fix has now been merged into 6.44 [r3583] and 6.36 [r3584].
Related
Commit: [r3583]
Commit: [r3584]