XSL files are so-called XML style sheets, with which the appearance of the elements of an XML document can be influenced. For example, you can set properties such as the color and size of text and tables using the XML Style Sheet Language.
The functionality is very similar to CSS / HTML.
XSL files are pure text files that can be opened and edited in any text editor. However, there are several developer editors that simplify working with XSL files. The Eclipse development environment can be extended to handle XSL files with the OrangevoltXSLT plugin or the Web Tools Platform Project plug-in.
XML style sheet files are used in addition to web applications by various PC programs such as Microsoft Office (eg styles), Inkscape and FileMaker (design template for Database Design Reports) for the design of XML output.
Most often resolving problems with opening XSL files is very simple. Just install an appropriate program that supports such files. All of the listed programs support XSL files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of XSL files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate XSL files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the TextMate applications is not on the list, select "Browse" option in order to manually locate the directory where TextMate has been installed.
Sometimes problems with opening XSL files may not lie with the application itself, but can arise due to other causes, such as: