When the content entity has been fetched there are a number of attributes that can be applied to transform the entity elements and attributes. You often need to do this in order to prepare the content entity for presentation. Post-processing of data, for instance replacing NULL values from a databaser query with some other string, is another reason to apply transform attributes.

There are a number of attributes that carry out a specific operation but you also have full access to the whole transformation capabilities of XSL-T.

Note that the transform attributes will be applied in the order they are written in your content entity element. It is also possible to apply the same transform attribute several times on your content entity. However, you need to follow the syntactic rules of XML and therefore need to enumerate your attributes uniquely, like entitytransform_1, entitytransform_2 et c.