The file extension OTP identifies the templates for the presentations of the OpenSource application OpenOffice.Org Impress.
An OTP file contains formatting information, fonts, colors, but can also contain text and images. Otp files can also contain macros. These macros may contain malicious code, which is why you should do a virus scan before running it.
The OTP format is part of the Open Document for Office Application Standard, also known as OpenDocument. Originally developed by Sun Microsystems and based on XML, the standard has been defined and developed by the Organization for the Advancement of Structured Information Standards (OASIS).
OpenDocument is the native format of OpenOffice.Org Suite. Otp is a standard version of the presentation software OpenOffice.Org Impress.