txt From the 70's to 2007 the open source .txt filename extension format commonly referred to plain text documents encoded using the ASCII character set. To support internationalization and localization, .txt text documents are today text files encoded using the UTF-8 or UTF-16LE standard which is a superset of the ASCII character set. Text documents of type .txt typically have minimal formatting for example no support for bold or italic characters or support for bullet points etc. This allows .txt documents to use minimum storage space and be platform independent as long as the operating system supports the underlying encoding character set used to create the .txt document. On windows .txt file support has existed since 1985 when Windows 1.0 was released and since then has been mostly associated with the notepad application on Microsoft Windows.
lit The .lit filename extension, short for literature, is a proprietary filename extension of the eBook file format LIT developed by Microsoft. The format was initially released in 2000 and at the time was only compatible with Microsoft Reader. Though DRM support was one of the strong selling points of the LIT format, wide spread DRM circumvention discounted its utility in favor for competing open formats. This among other reasons caused Microsoft to officially discontinue support for the format by 2011 and cease further sales of eBooks based on the format completely by 2012.