In the A5E Tools Psion it lists Psionic Specialty, consistent with what is in the A5E SRD for chapter 2 of the Voidrunner's Codex. I believe this is what is listed as Mental Discipline (1) and (2) on the Psion class level table.
However, in the A5E Tools Psyknight it also lists Psionic Specialty, which is not in the SRD, and I presume a cut-and-paste error from Psion.
In the drop down menus, the destination for the Rules - Spells - Druid, brings you to the spell list filtered for Clerics instead of Druids as intended. All the other class spell list links from Rules - Spells - Classname work correctly.
In the Voidrunner's Codex page 139 and correspondingly on the Trooper class wiki, it specifies in the text that "At 1st level you gain two drills of your choice, detailed at the end of the class description." However, in the table of class features vs. level for Trooper, it specifies only 1 drill is known at level 1 and 2. I would assume from this that the text description has the typo and should state "one drill" rather than two.