Please help me out..What is the Exact functionality of Template Building Block.. From my knowledge it is used for creating customized functions...But really am not able to understand it
Template Building Blocks are executed when you publish something. They are used to transform your content, which is stored as XML in the content manager database, to something that your web application needs (typically html or, in cases like DXA and DD4T, JSON).
This type of question is what most people here would consider "basic knowledge", so it may be considered a very wide-open question.
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