Unity uses predefined sets of shaderA program that runs on the GPU. More info See in Glossary keywords to generate shader variants that enable common functionality.
Unity adds the following sets of shader variant keywords at compile time:
By default, Unity adds this set of keywords to all graphics shader programs: STEREO_INSTANCING_ON, STEREO_MULTIVIEW_ON, STEREO_CUBEMAP_RENDER_ON, UNITY_SINGLE_PASS_STEREO. You can strip these keywords using an Editor script. For more information, see Shader variant stripping.
By default, Unity adds this set of keywords to the Standard Shader: LIGHTMAP_ON, DIRLIGHTMAP_COMBINED, DYNAMICLIGHTMAP_ON, LIGHTMAP_SHADOW_MIXING, SHADOWS_SHADOWMASK. You can strip these keywords using the Graphics settings window.
In the Built-in Render PipelineA series of operations that take the contents of a Scene, and displays them on a screen. Unity lets you choose from pre-built render pipelines, or write your own. More info See in Glossary, if your project uses tier settings that differ from each other, Unity adds this set of keywords to all graphics shaders: UNITY_HARDWARE_TIER1, UNITY_HARDWARE_TIER2, UNITY_HARDWARE_TIER3. For more information, see Graphics tiers: Graphics tiers and shader variants.