This design task is related to D5292: Cycles: LookDev Mode
We will change the shading mode design to clarify the purpose and make look dev features available to Cycles and external renderers. This means the following.
LookDev shading mode is renamed to Material Preview. It always uses Eevee as the renderer, and is intended to provide a fast material preview suitable for texture painting, and texture and material setup.
The "Use Scene Lights" and "Use Scene World" options will be removed, and it will always use HDRIs for lighting.
Further, there will additional options to disable some effects that are slow or get in the way of setting up materials. These would be things like depth of field, motion blur, indirect light or bloom, and be disabled by default. The purpose here is not to provide all Eevee renderer controls, just a commonly useful subset. This is not a requirement to be added immediately, and can be done later.
Rendered shading gains "Use Scene Lights" and "Use Scene World" options previously in LookDev. These will be enabled by default. When off, HDRIs will be used for lighting instead.
Renderers will be able to customize the shading settings panel and add additional settings. For example choice of render passes to use instead of combined or render quality controls. This is up to each renderer and is not a requirement to be added immediately.