Yeah, i think it would be useful if the 'pedia could support arbitrary articles and catagories.
Categories no, but you can show arbitrary stringtable entries in the pedia by making a link to it using the internal link format.
A normal bit of content reference looks like [[tech TECH_NAME]] which will make a clickable link out of the stringtable replacement for TECH_NAME to an article about that tech. Internally, this works by being replaced by some text like <tech TECH_NAME>Human-Readable Tech Name</tech>. This is interpreted by the encyclopedia as a link, and Human-Readable Tech Name gets underlined with a link to the article on the tech TECH_NAME.
Something similar exists for arbitrary text, though not with the understanding of what the text means. You can add some text like <encyclopedia SP_GYISACHE_DESC>[[SP_GYISACHE]]</encyclopedia> which will be replaced by Gyisache underlined as a link. Clicking the link will go to a page that is the text in the stringtable entry SP_GYISACHE_DESC, but with no title or other information.
To make proper encyclopedia entries fully customizable, there'd probably need to be a separate file listing the articles, with separate title and main text fields, and probably something about how to index or categorize them.
What do you all think of changing the pedia entries to something like this:
"... adds +1 population capacity per planet's size level.."
instead of the current,
"Increases the population capacity of Poor planets to 1, 2, 3, 4, and 5 for Tiny, Small, Medium, Large and Huge planets, respectively."
I think it's better as it is. Introducing extra concepts that require a linked page to explain is needlessly complex when a single line of text explains it on its own.