Fabric

Fabric is a lightweight modloader, that also has a separate API required in the mods folder. It has been worked on alongside the 1.14 snapshots of Minecraft Java Edition since before snapshot 18w49a (before December 5th 2018). But this is evidence of public releases, not much is known of it's creation prior to this.

Wiki cleanup note: Information will come from the Fabric Wiki, Curseforge, Minecraft Forums (specifically the Fabric Discussion Section thread) mainly for sources that can be cited. Not all is able to be put accurately but sources will mainly come from those known sources for installation, or other information related to the Fabric Modloader, Fabric API and mods that support it.

Background:

Known Installation Methods Of Fabric: MultiMC was the first Launcher (while Third Party) to support Fabric Modloader.

The Minecraft Java Edition Launcher was supported not long after 18w50a via the Fabric Installer.

Installation Instruction For Minecraft Java Edition Launcher: Fabric Installer is the tool/method to make instances of 1.14 Minecraft Java Edition snapshots from 18w49a and onwards release versions of Minecraft to be modded (public knowledge, but not accurate), Fabric API is a core mod of sorts for mods. It is best to not get these mixed up.

Fabric Installation Instruction can be found on the Fabric wiki here: http://fabric.asie.pl/wiki/install

Download Fabric Installer from modmuss50's jenkins: https://jenkins.modmuss50.me/job/FabricMC/job/fabric-installer/job/master/

A step by step process is available below.

Fabric is installed into the Minecraft Java Edition Launcher from a tool on the Fabric Wiki here: http://fabric.asie.pl/use/ This source has two MAIN methods, one for MultiMC, and the Minecraft Java Edition Launcher (Vanilla). Since this is for the Vanilla method, select that tab and Click the 'download.jar' button for the Installer. Once it's downloaded, double click it like you would Forge or Rift.

There is a few options to be aware of.

Once Fabric has installed it's profile (if you choose to, it's best to do this the first time you install Fabric), you either have it installed for you, or you have to select the Fabric version from the Launch Options tab. You can also switch Fabric snapshots at any time from the Launch Options to update as well and use the same profile, just untick the Create profile check box to do so and it won't create a profile but will install the updated Fabric snapshot you wanted.

Fabric API is also needed to make mods possible to run in this instance (not all but many do require it). Fabric API is like a library mod that is required by mods that are in the Fabric environment to work. The common source to get Fabric API builds is from Curseforge.

Once Fabric API (Minecraft Java Edition not just Fabric Modloader snapshots) is downloaded and put into the mods folder along with some mods your good to load the game and play. Sometimes, when Minecraft snapshot versions bump, Fabric API may need an update as well.

'''Note: Like Rift, or Forge for Minecraft 1.13.2, Fabric does not read mods in individual folders. While Forge might have been able to read folders from 1.12.2 when they were put into it, Fabric cannot.'''

Curseforge source for Fabric API builds: https://minecraft.curseforge.com/projects/fabric

OptiFabric (Optifine + Fabric) for 1.14.2 Tutorial Instructions (Although "Unsupported" now it is possible to get working still if interested)

Vanilla Instructions:

Once you have a modded Fabric setup, you just download Optifine (https://www.optifine.net/downloads) from the legitimate source (not mod repost sites tricking you), and go to the downloads, and select from the preview versions (at the time of typing this, it might be changed to be listed normal once it's more 1.14 ready) and put the Optifine preview file into your mods folder alongside OptiFabric which you can get from here: (https://minecraft.curseforge.com/projects/optifabric) to use for compatibility between the two. One thing to consider with the OptiFabric installation is that you can either use the preview file as is (out of the box) or extracted and you will get the same result (this is not the case with other modloader installations as far as it is known when it comes to OptiForge or OptiRift), but without OptiFabric it will not work with a Fabric created instance [this applies to both the Preview file and the extracted method] (this is unrelated to the Optifine install for Vanilla 1.14.2 and only applies to Fabric modded instances for 1.14 versions). Once it's loaded up you should be good to go playing Fabric mods alongside Optifine.