Editing XPInstall

{{Short description|File format standing for Cross-Platform Install}}
{{Multiple|
{{More citations needed|date=February 2024}}
{{Update|date=December 2016}}
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{{Infobox file format
| name          = XPInstall (XPI)
| screenshot    =
| caption       =
| extension     = {{mono|.xpi}}
| mime          = application/x-xpinstall
| owner         = [[Mozilla Foundation]]
| genre         =
| container for =
| contained by  =
| extended from =
| extended to   =
}}
'''XPInstall''' (Cross-Platform Install) is a technology used by the [[Mozilla Application Suite]], [[SeaMonkey]], [[Mozilla Firefox]], [[Mozilla Thunderbird]] and other [[XUL]]-based applications for installing [[Add-on (Mozilla)|Mozilla extensions]] that add functionality to the main application.<ref name="Fisher2009">{{cite web | last1=Fisher | first1=Tim | date=2009-02-16 | title=What's an XPI file and how do you open one? | website=Lifewire | url=https://www.lifewire.com/xpi-file-2622582 | access-date=2024-02-23}}</ref><ref name="File_org2023">{{cite web | author=File.org | date=2023-02-24 | title=XPI File: How to open XPI file (and what it is) | website=file.org | url=https://file.org/extension/xpi | access-date=2024-02-23}}</ref>

A XPI (pronounced "zippy" and derived from XPInstall) installer module is a [[Zip (file format)|ZIP]] file that contains an install script or a manifest at the root of the file, and a number of data files.<ref name="Fisher2009" /><ref name="File_org2023" />

In Mozilla, Firefox before 0.7, and before 0.5{{what|date=December 2016}}, the package contained a [[JavaScript]] install script (install.js) with '''some''' directives for actions to take during an install, including adding files and directories, removing old or obsolete files and directories, executing command line tools, etc. In middle-old Firefox and Thunderbird versions, the install script has been replaced by a [[UI chrome|chrome]] manifest and a [[Resource Description Framework|resource description framework]] file (install.rdf). Since Firefox version 45, the only mandatory file is manifest.[[JSON|json]].

Since Firefox 1.0, XPIs from sites other than [[Mozilla Add-ons]] are blocked by default. This was an attempt to prevent malicious programs, like [[computer virus]]es, [[Trojan horse (computing)|Trojans]] and [[spyware]], from being installed by novice users. While it is possible to put a site into the [[whitelist]] that limits sites which can install XPIs, malicious sites cannot install extensions in the background (without human intervention). This is because a confirmation dialog needs to be answered for every single installation of an extension.

However, users are still advised to install extensions from trusted sources only.

== Applications with built-in support for XPInstall ==
=== Web browsers ===
* [[Mozilla Application Suite]]
* [[Mozilla Firefox]]
* [[Flock (web browser)|Flock]]
* [[SeaMonkey]]
* [[Netscape Browser]]

=== Other applications ===
* [[Nvu]] (web authoring application)
* [[Songbird (software)|Songbird]] (media player and organiser)
* [[Mozilla Sunbird]]
* [[Mozilla Thunderbird]]
* [[Google Gears]]
* [[Zotero]] (bibliographic reference management software)

== See also ==
* [[Mozilla Archive Format]]

== References ==
{{Reflist}}

== External links ==
{{Portal|Free and open-source software}}
* {{cite web | url=https://www.mozilla.org/projects/xpinstall/ | archive-url=https://web.archive.org/web/20090422015912/http://www.mozilla.org/projects/xpinstall/ | archive-date=2009-04-22 | title=XPInstall |access-date=2021-09-28 }}
* {{cite web | url=https://developer.mozilla.org/en/docs/Extension_Packaging | archive-url=https://web.archive.org/web/20080819132008/https://developer.mozilla.org/en/docs/Extension_Packaging | archive-date=2008-08-19 | title=Extension Packaging – MDC |access-date=2021-09-28 }}
* {{cite web | url=https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Your_first_WebExtension | title=Your first extension – Mozilla &#124; MDN | access-date=2021-09-28 | date=2021-02-19 }}

{{Mozilla projects}}

{{DEFAULTSORT:Xpinstall}}
[[Category:Archive formats]]
[[Category:Firefox add-ons]]
[[Category:Firefox extensions]]
[[Category:Installation software]]
[[Category:Mozilla]]
[[Category:Package management systems]]