At first glance, it might look like the T Block is used to stiffen panels over vent openings.  No vent opening is shown in this detail.  However, a vent opening detail would be a beneficial addition to the standard such as this.


This detail from FEMA DR-4193-RA2 does not include a T Block.

T Blocks have not been tested or even considered as something that should be tested by the APA, nor do they appear in any of their details.


Figure 7, American Plywood Association Introduction to Lateral Design


American Plywood Association, Figure 4, Building for High Wind Resistance in Light-Frame Wood Construction