Before reading on, you should know some definitions used in this documentation:

• element aka tag: an instruction used to tell the package manager what to do. ie <install></install>
• attribute aka property: an additional value used to describe an element
• inline: code or text that is written in this file instead of coming from an outside source
• file: the name or location of a file to be used instead of "inline"
• location aka path: the location on the computer of a directory and/or file
• ignore: used to ignore an error
• skip: skip this operation/file
• fatal: stop the entire modification and return an error

There are also variables that may be used in place of a path. Italics denotes the commonly used path so you get an understanding of what the variable references.

• $boarddir: The directory where index.php is found. Usually one level beneath the source files are contained.
• $sourcedir: The directory where the source files are contained (ie Post.php, Admin.php, etc) /Sources
• $avatardir: The directory where the avatars may be found /Avatars
• $themedir: The directory of the default theme
• $themes_dir: The directory containing the default, and other themes
• $imagesdir: The images directory of the default theme
• $languagedir: The location of the directories of language files
• $smileysdir: The location of the smiley directory

modification.xml All elements, unless otherwise stated, are not optional and contain no attributes.

• <modification></modification>

• Must encompass all other elements in the file.
• Attributes:
  • xmlns: defaults to "http://www.simplemachines.org/xml/modification"; optional
• <id></id>

• Contains the id of the package. Should be in the format of [username]:[package name]. For instance groundup:bestmod When submitting a mod to the mod site, the username should be your username from www.simplemachines.org
• <version></version>

• The package's current version.
• <file></file>

• The file to modify. Including all of the operations to take on this file.
• Attributes:
• name: the name of the file and path
• error: what to do when this file cannot be modified; "ignore" "fatal" or "skip"; use "ignore" to create a new file; optional; default to "fatal"
• Elements:
• <operation></operation>
• An operation to be perfomed on this file
• Attributes:
• error: what to do if this operation can not be performed; "ignore" "fatal" or "required"; use "required" if this operation must fail; defaults to "fatal"; optional
• Elements:
• <search></search> or <search /> (for use with position="end" only)
• The code to search for
• Attributes:
• position: the position of where the search code should exist after changes: "before" (to put the code before your addition), "after" (to put the code after your addition), or "replace"; required
• whitespace: Whether to ignore whitespace or not: "exact" (default) or "loose"; optional; default: exact
• regexp: If the search is a regular expression or not. "true" or "false"; optional; default: false
• <add></add>
• The code to add