Not sure if this was posted here by a wonderful fellow named "frostbite305" who did the work and posted it on Reddit, but I figured I'd link to it and briefly explain it to the best of my ability. If this was posted here by frostbite305, I do apologize in advance for this thread. All praise be to frostbite305. Seems there's two new entities that have been in the game for a short time, but they weren't added to the FGD files. One can easily create a custom FGD file specifically for these two things (that's what I did), but for now I'm thinking maybe Boojum can toss these two entities into the Ultimate Mapping Resource Pack's FGD as part of an update. https://www.reddit.com/r/tf2/comments/42uawc/psa_for_mappers_i_added_the_documentation_for_a/ (Click the entity names below to view the Valve Developer Wiki article for the entity. At the bottom of both articles is the custom FGD code you can copy and paste into "tf.fgd", "tf-abs.fgd" (if you use the UMRP) or a custom-made FGD file) First up we have "trigger_add_or_remove_tf_player_attributes". Similar in function to SourceMod's TF2Items extension and how that allows us plugin coders to add/remove attributes to players, this brush does basically the same thing. Apparently the "Remove" portion isn't functional at this point in time, but the Add portion does allow you to set a duration for the attribute chosen. Secondly, this one has been in since a recent PASS Time update, "filter_tf_class". Does exactly what the name suggests. Allows filtering based on the PLAYER's class. Do not get this confused with "filter_activator_class". filter_tf_class could be used for restricting entry to an area unless you're a specific class. Attached to this post is my own custom made FGD file containing both the trigger_add_or_remove_tf_player_attributes and filter_tf_class entities. Once you've downloaded tf-hidden.fgd, drop it into "C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\bin". Fire up Hammer, click "Tools" and then click "Options". To the right of the Game Data files box are some buttons. Click "Add" and select "tf-hidden.fgd". Restart Hammer and you'll be able to access both brush entities.