Optionally, defines the literal XML structure and specific nodes or computations to include in the result when loops are processed concurrently for <foreach>. If this is omitted, loops are processed concurrently, but the results of each loop are not bound to any variables.

How results for each loop are fused together and assigned to variable(s) depends on the value of the merge attribute in <foreach>. The <fuse> outputvariable attribute identifies the variable for the fused result, and if applicable the base name for variable names for the results of each loop.