From the author's README on Thunderstore

FTP Black Tee

A black tee with a white FTP logo.

Front — small FTP on the chest
Back — large FTP across the upper back

Install

Extract the FTP_Black_Tee folder into your ReSkate mods folder:

<ReSkate>\Mods\FTP_Black_Tee\

The default location is:

C:\Games\Skate\Mods\

Launch ReSkate and the mod is picked up automatically. To equip it, open the character's clothing and select the tee on the top slot.

If it does not show up, open the Mods tab in ReSkate Studio and make sure FTP_Black_Tee is ticked in the load order.

Uninstall

Delete the FTP_Black_Tee folder from Mods\ and relaunch.

Notes

Built with ReSkate Studio from the native Own_TopShirt_Gen_TshirtOverLongsleeve_00001 cosmetic. The base mesh, fit, stitching and sleeves are the game's own — only the base colour texture is replaced, so it will layer normally with whatever longsleeve you have equipped.

Install Lil Peep Hellboy Whitetee

You need ReSkate and your own copy of skate. on Steam.

Open ReSkateLauncher.exe and go to MODS.
Search for Lil Peep Hellboy Whitetee and click install. The launcher also installs anything it depends on.
Press PLAY. In game, the MODS tab of the ReSkate menu (Insert) turns it on and off.

Or install it by hand: download the .zip and drop it on the launcher window, or unzip it into its own folder in Mods\ beside Skate.exe.

Maps show up in the ReSkate menu's level list. To join a server running a custom map, you need the same map installed. If the game won't load after installing, see known issues.

skatemods doesn't host or review this mod. The download comes straight from Thunderstore. Only install mods you trust, because scripts can run code.