SequenceHold

SequenceHold is an attribute that specifies that Sequence objects appearing in the arguments of a function should not automatically be flattened out.

Examples

Without SequenceHold, Sequence is flattened:

f[Sequence[a, b, c]]
(* f[a, b, c] *)

With SequenceHold attribute:

SetAttributes[g, SequenceHold];
g[Sequence[a, b, c]]
(* g[Sequence[a, b, c]] *)

Please visit the official Wolfram Language Reference for more details.