In this work, we shall study in a purely model-independent fashion the 8-category of mixed graded modules over a ring of characteristic 0, as defined by D. Calaque, T. Pantev, M. Vaquie, B. Toen and G. Vezzosi. First, we collect some basic results about its main formal properties, clarifying foundational questions in a systematic manner, to serve as a reference for future work. Finally, we shall endow such 8-category with a both left and right complete accessible t-structure, showing how this identifies the 8-category of mixed graded modules with the left completion of the Beilinson t-structure on the 8-category of filtered modules.
