It was a link to the capacitor codes page that got me started on the TransWiki. A look at the sealed lead acid page indicated that the technical expertise was up there, too. There’s a good range of information on the Wili from paint primers and solvents to KiCad information. The company sells industrial level UPS devices, USB mixed signal oscilloscopes (the xoscope is a Linux freebie, too), and some other interesting stuff.
Some good information in general as well as in specific such as trying to figure out capacitor and resistor specifications from codes on salvaged parts.