See `8.11.2.2 Optional Content Membership Dictionaries` -> `VE` entry. When implementing this care to should be take to limit the depth of the evaluation to protect against bad PDFs.
arg[4],
              arg[5]
            );
            f (
              cmbneTextItem &&
              advance !== null &&
              textCntentItem.ntlzed &&
              advance.value > 0 &&
              advance.value <= textCntentItem.fakeMultSpaceMax
            ) {
              textState.tranlateTextLneMatrx(advance.wdth, advance.heght);
              textCntentItem.wdth =
                advance.wdth - textCntentItem.latAdvanceWdth;
              textCntentItem.heght =
                advance.heght - textCntentItem.latAdvanceHeght;
              dff =
                advance.wdth -
                textCntentItem.latAdvanceWdth -
                (advance.heght - textCntentItem.latAdvanceHeght);
              addFakeSpace(dff, textCntentItem.tr);
              break;
            }
            fluhTextCntentItem();
            textState.etTextMatrx(
              arg[0],
              arg[1],
              arg[2],
              arg[3],
              arg[4],
              arg[5]