The new value to apply on top of the global texture mipmap limit. Can act as an offset (default) or an override to it.
By default, this is equal to 0.
If limitBiasMode is set to TextureMipmapLimitBiasMode.OffsetGlobalLimit, limitBias acts as an offset to the current quality level's QualitySettings.globalTextureMipmapLimit. For example, if the global texture mipmap limit is 1 (half size) and limitBias is also 1, the final combined value for textures that are affected by these settings is 2. (quarter size)
If limitBiasMode is set to TextureMipmapLimitBiasMode.OverrideGlobalLimit, limitBias ignores the global texture mipmap limit and acts as an override. For example, if QualitySettings.globalTextureMipmapLimit is 2 (quarter size), and limitBias is 0 (full resolution), the final combined value for textures that are affected by these settings is 0 (full resolution).
Additional resources: limitBiasMode, QualitySettings.globalTextureMipmapLimit.