SCART pinout specs (Euro Scart)
Note: this is for Euro Scart and not JP21 Scart
This updated diagram makes it easier to see which way you are looking at the SCART connector, and also shows the female and male versions of the connector.
If you are outputting RGB signal from a device, you will need to make sure the correct side of the cable/connector is connected. This is because sync and audio can be affected if the wiring is not correct.
XRGB mini pinout specs
XRGB mini is a less formal RGB connection style that the retro gaming community has adopted as a kind of de-facto standard. It has slowly become a popular choice for retro gaming mods over the years. The pinout standard was likely adopted from the Framemeister XRGB-Mini.
8 pin XRGB mini spec is used by Tim Worthington for the NESRGB and for a no-cut Atari 2600 mods. It is also great for modders who want to create custom RGB cables for devices that don't have standard multi-out AV ports. This pinout is convenient because it allows for a lot of flexibility in terms of what devices can be used with it. Additionally, it's great for CRTs that are small and don't have the space to accommodate a full SCART port.
However, there is a little nuance with the way we want the XRGB mini pinout to work on a CRT. One of the pin in the middle section (brown circle on the picture above) is reserved for +5V blanking signal. If you want your CRT mod to not use a physical blanking switch, it is important to make sure this 5V can be used for blanking purposes. Some of the passive XRGB mini to Female SCART cables sold by vendors like retrogamingcables.co.uk were missing this 5V. Therefore, please make sure to purchase the correct cable. You can also try purchasing a fully wired XRGB mini to male SCART cable and then wire your own female SCART connector head to the end if needed.