This account is a bot account used to host the Ultraviolet userscript. It is owned by User:Chlod and is used for continuous deployment. This account is not accessible by any other Ultraviolet team members, other than via an OAuth 1.0a token used for continuous deployment held securely that can be revoked at any time by User:Chlod. If you would like to learn more about Ultraviolet, click here.
The username "10nm" comes from the lower limit of the range of ultraviolet light wavelengths on the electromagnetic spectrum — 10 nanometers.