Important Information

Updated: September 2026

Keeping this accurate

Anything load-bearing - a number, a rule, a mechanism - is worth confirming at the primary source first. That is not a use this material is warranted for.

Sites linked from here

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Changes to this page

Where this needs updating, the new wording replaces what came before from the moment it is published on this page.

Reporting an error

Email [email protected] about what is explained on this website.