12 hive - XML directory

In this post, I wish to explain each of the XML files found in the Templates\XML directory in 12 hive. Reason being I use this XML files once in a while to tweak my SharePoint installation. I will explain this in detail as I unleash each of the XML files.

alerttemplates.xml 
Used to change the look and feel of Alert Notification emails for each list, web or custom types in your SharePoint Environment. You can set custom branding based on your to your email alerts.

BASE.XML
BASE.XML defines base types for lists that apply globally to all the SharePoint Web sites.

DOCICON.XML
This file is used for mapping file types to particular icons. To add the new icon to the file type follow below steps.

1. To add a .pdf (Adobe PDF) file name extension, add the following line to the ByExtension section in this file—<Mapping Key="pdf" Value="pdf16.gif"/>.
2. Add the file pdf16.gif (use Google Image Search to get this image) to the Program Files\Common Files\Microsoft Shared\web server extensions\12\Template\Images.

FLDTYPES.XML
Used to define how various SharePoint field types are rendered. For further info check out here.

fldtypes_hold.xml
Used to define the hold status pertaining to entities realted to Records Management Policy. Note: This file is meant for internal use and it is recommended not alter the contents.

fldtypes_publishing.xml
Used to define the publishing field types like HTML, Links, Summary Links etc. In case of creating a bew custom publishing field type, say Address (with validation) then a new entry related to this filed type has to be added to this file.All other xml files with prefix fldtypes are cutom built field types. Yet another notable field type is Business Data field. This field type is defined in fldtypes_spsbizdata.xml.

htmltransinfo.xml
Used to define the how to open various documents stored in the sharepoint server. The mapping entry for a particular document in this XML file will tell SharePoint server to open the document in a particular client application. If the document conversion mapping is not found in this file, SharePoint will prompt the user to download the document.

SharePoint is flexible enough for you to create custom properties by creating custom XML files in this directory.