Where can I check all the installed Magento extensions in the admin panel?
How to check all installed in Magento extensions?
php;magento
There's a lot of confusion around terminology here.  Magento, the programming system, has code Modules.  These modules are often (incorrectly, although I've done it myself) called extensions.  Modules allow you to add code to Magento's configuration based MVC system.  Magento also has a system called Magento Connect.  Magento Connect allows you to install extensions.  Magento Connect extensions are special pear packages.  These packages can install a file anywhere in the Magento system.  An extension may contain many Modules.  It may also contain arbitrary files that are not part of a module.There's no formal place to check which modules are installed in Magento.  Informally, people use the Disable Module Output configuration section at System -> Configuration -> Advanced -> Disable Modules OutputThis section will create a list of each programatic module installed in the systemFor Connect extensions, go to System -> Magento Connect -> Magento Connect ManagerThis is where you're supposed to install/remove/manage your connect extensions.  There's still the problem of manually installed extensions.  Magento doesn't offer a formal marketplace.  Many third party extension developers have created their own installer systems, or else have you install their files manually.  There's no way to track these extensions other than diffing your code-base.