It adds a lot of options to various entities to make them more useful.

Note: You should change the default entity from info_survivor_position to something else like info_player_start. Somehow changing from info_survivor_position fo env_sprite crashes hammer.

1. "Fade Distance" sphere helper to areaportal_window entities so you can easier pick where the fade starts and ends.
2. Ammo upgrade entities as already deployed versions.
3. New visgroups for many type of entities.
4. Default models for many props, like weapon_ammo_spawn, trigger_finale...
5. More useful melee spawner that lists all usable melee weapon names in the help box, to copypaste names. Along with a model picker to easily pick any helper model you want. Also has a helper model browser that's just there to find a custom melee model, so you can copypaste the path of the model into the helper model field. It's a bit weird, but the best setup that i can do.
6. info_survivor_position entities that allow you to pick the player model to align intro sequences.
7. Marking leftover unused entities as Obsolete with the apropriate icon.
8. A whole lot of entity fixes specific for L4D2. Some values have been removed because L4D2 does not have them (Like "World Is Cold" in worldspawn), or the entity settings like adding Parentname to prop_physics, amongst other things.
9. Generic helper models for all weapon_spawn, item_spawn, upgrade_spawn. To diferentiate specific weapon spawnpoints from randomised spawns.
10. Helper meshes for env_sprites, which are balls colored in the same color sprites are colored. Furthermode, all sprites are now "World Space Glow" by default, which is what lensflare sprites usually always are supposed to be.
11. A bunch of new iconsprites and helper models for some often used entities, to differentiate them better.
12. Optional color helpers for point_spotlight. unfotunately you have to manually set the color by copypasting the brightness value into the helper color field. If you don't, the color will default to turquoise. But this can help you remind yourself what color the light has without having to click on the entity.
13. Worldspawn settings to choose a Skybox, Music Post-String, Witch behaviour, and "Detail material type" from a choice list.
14. Added the alleydirt_leaves and urban_overgrown_docks $detailtype that valve forgot to port to L4D2. Former was ported from L4D1, latter was made up my myself.

Contains a VPK for hammer, including:

1. Tool textures specifically for every kind of tool brush entity. like trigger_once, trigger_hurt, info_changelevel...
2. A lot of new sprites for entities that didn't have one. Like the director and icons for all three tonemap entities.
3. various differently colored sprites for logic_relay. For people who like to color code their things.
4. L4D2 specific measure textures for doors, jump height, crouch space...
5. Aforementioned alleydirt_leaves and urban_overgrown_docks $detailtype, with the required detail.vbsp

1. Download the entire "L4D2-FGD-Edits" repo folder into Steam\steamapps\common\Left 4 Dead 2\bin
2. You should end up with the directory Steam\steamapps\common\Left 4 Dead 2\bin\L4D2-FGD-Edits
3. In hammer click on Tools - Options
4. In the "Game Configuration" tab, look for the "Game Data Files" box use ONLY the left4dead2_ADDON.fgd.
5. Open Steam\steamapps\common\Left 4 Dead 2\left4dead2\Gameinfo.txt
6. Scroll down to the first few game lines.

Game	update
Game	left4dead2_dlc3
Game	left4dead2_dlc2
Game	left4dead2_dlc1
Game	|gameinfo_path|.
Game	hl2

8. Add the folowing above Game Update

Game bin\L4D2-FGD-Edits-main\hammer_vpk

Note:

Here are images of some abilities that have been added or changed.

Areaportal Distance Picker.

Already deployed upgrades.

More Visgroups.

Better Melee spawn.

Info_survivor_position with helper models.

Obsolete's unused or not programmed entities.

More specific tool textures.

Blend Textures displaying what detail they use.

Optional Generic helper models for randomized weapon spawns.

Ball helper models for env_sprite.

More helper models, each camera entity got a different color. Orange Freeman there is info_teleport_destination.

Light_spot entities can be colored.

New icon sprites.

Worldspawn settings.