What is .SE file extension?
File containing code written in the Shuttle language, a lightweight markup language that can be converted into HTML5.
Some syntax rules include:
Text is converted into blocks of text that are separated by a blank line
A header begins with a #, with the number of #s preceding the header signifying the heading level number.
Ordered lists use numbers with a period, while unordered lists just use hyphens.
Links are inline  () or reference  , while link definitions can be used anywhere in the document. One blank space is allowed between the two parts of the link.
Images function the same as links but the syntax begins with an exclamation mark (!).
Horizontal rules are created with three or more hyphens.
NOTE: Shuttle converters are available for conversion to Java and PHP.
You can see a list of software programs here on easyfileopener.org that can open this file type so that you don’t need to search for it on the web. You can then open your file with this extension using a software listed below.