Из описания MR Tech's Disable XPI Install Delay:
Замечания по поводу переводу принимаются, высказывайтесь в PM.

Данная тема посвящена обсуждению расширений MR Tech's Local Install, а также входящих в его состав расширений MR Tech's About:About и MR Tech's Disable XPI Install Delay.

Позволяет автоматически архивировать, устанавливаемые из интернета расширения.

интегрировано часть (а может и почти все) функций nightly tester tools.

кстати в последнююю версию (та что ещё в разработке)

# Added: Special routine to Extension manager automatically detect and prompt to uninstall any of the 15 extensions that are already integrated with Local Install, for 1.5 Beta it will also prompt to restart.
# Added: Merged "Show Failed URL" code so you can now disable that extension (not needed and automatically disabled with Firefox 1.5 and above).
# Added: Merged and Enhanced "Restart Firefox" code to work with Firefox & Thunderbird 1.4+ builds, it will also now close all child windows before initiating the restart command.
# Added: Added "Restart ..." menu options to main window and EM/TM File menus.
# Added: Merged and Rewrote "Close All" (Windows) code which will automatically close child windows when closing the main browser or mail window, so you can now disable that extension.
# Added: Tons of report display options for "My Config" in Local Install Options window.
# Added: Custom Style Sheet Entry for "My Config" in Local Install Options window.
# Added: "Refresh" and "Options" buttons to main "My Config" window.
# Added: "Find Updates" option to EM/TM Tools menu for Deer Park/Branch/Trunk builds to find updates for all extensions/themes.
# Added: "Make Compatible" option to EM/TM Tools menu for Deer Park/Branch/Trunk builds to update all non-compatible extensions.
# Added: Merged "Make Compatible" XPI install code from Nightly Tester Tool as it wasn't working if Local Install was installed, you really shouldn't need NTT installed, I'l make sure to coordinate with the developer in case I run into problems.
# Added: Right-Click "Make Compatible" feature from "Nightly Tester Tools" to help with upgrading from 1.0 to 1.5 Beta 1
# Added: Extended "Make Compatible" functionality from "Nightly Tester Tools" over to Themes to help with bumping them up too, enjoy.
# Added: "View My Config" to Tools|My Config & EM/TM Tools menus
# Added: Changing EM listing background color of extensions that willl be disabled on restart to grey to mimic 1.0.x behavior
# Added: New tooltips for View My Config and JS Console toolbar buttons.
# Added: JavaScript Console Toolbar Button will now be toggled/untoggled to match js console state.
# Added: Locale directories now have a WinMerge properties file to help with merging and debugging (please use this with the Unicode compatible version, thanks).
# Updated: Rewrote Toolbar button toggle logic to fix mismatched disabled/enabled states and support for multiple browser window updates.
# Updated: Localized all new labels for My Config window and for My Config settings
# Updated: Optimized enabling "Apply" button on click for Settings window
# Updated: Complete rewrite of "Close All" function code
# Updated: XPI Install Delay code was cleaned up of redundant overlay code
# Updated: Now hiding XPI Install "make compatible" checkbox for Firefox 1.0.x versions
# Updated: Simplified the Enable/Disable All Extensions code in the Extension Manager
# Updated: Minor Slim Mode skin cleanup for 1.5 beta builds
# Updated: Minor skin change to for Thunderbird overlay (might require uninstall/reinstall)
# Fixed: Issues where Thunderbird would show corrupt icons on restart
# Fixed: Tons of Localization file tweaks and cleanup
# Fixed: Minor updates to Mozilla Suite installer
# Fixed: Finally fixed compatibility issues with Compact Menus and the Help|About: entries
# *Fixed: Slim mode now works properly with Aquatint theme

скорее всего нужно указать в настройках папку для сохранения..