Where do the race facts come from?
Only from the organiser: their race page, their GPX file, their regulations or runner's guide. Distance, climbing, aid stations, cut-offs, dates and start times are copied from there, with the date they were last checked. Nothing comes from race directories, other blogs or apps. Where the organiser's own figures disagree with each other, the page gives the figures from their course table and says what else they publish.
The pages are unofficial. Pendio isn't affiliated with any race or organiser, doesn't publish their GPX or their maps, and links to the organiser for the file and for everything about the race. If an organiser asks for a correction or for a page to come down, it does.
What does Pendio do with the GPX?
It runs the same analysis as the GPX course analyzer and the race planner at pendio.app/app. The course is resampled every 10 m and its elevation smoothed over 70 m, so GPS and barometer noise don't add phantom climbing; D+, D−, gradients and the 13 grade bands come from that smoothed line. A climb is a stretch steeper than +2 % (a descent, steeper than −2 %); a flatter break shorter than 150 m doesn't split it, and it counts once it is 200 m long or 12 m high. Only the numbers are kept: no coordinates, nothing that could rebuild the route.
A GPS track rarely measures exactly the organiser's distance. The page shows both, and the build refuses a file that measures more than 8 % away from the organiser's distance, as it is probably another course's.
What is the flat-equivalent distance?
The flat distance that would take as long as the course at the same effort. Every 10 m counts more or less than its length depending on its gradient, by a grade-adjusted pace model: climbs count for more, gentle downhills for less, and steep downhills for more again. Pendio's race plans use the same model to share a target time out between the legs.
What are the grade bands?
Every 10 m of the course goes into one of 13 bands by its gradient, from steeper than −20 % to steeper than +20 %; each page lists them under "The course in detail". "Flat" on these pages is the band within ±1 %; "climbing" and "descending" are everything steeper either way, so the three shares add up to the course. "Steeper than ±10 %" counts the three bands each side from ±10 % out.
What do "steep" and "very steep" mean on these pages?
Words for the ground, defined once. A climb or a descent is called steep from 10 % average grade over its whole length, and very steep from 20 %. Stretches inside it are steeper than its average; the tables give each climb's steepest 100 m. The words describe the slope, not how anyone should run it.
How are the legs and the cut-offs worked out?
Each aid station is placed on the GPX at the organiser's kilometre, scaled to the GPX's own length. A leg's effort is its share of the course's flat-equivalent distance: the share of an even effort it takes.
For each cut-off, the page gives the slowest finish time that still reaches it if you spread your effort evenly over the course and stop nowhere: the cut-off divided by the share of the course's effort done by then. The cut-off with the fastest such time is the tightest. It is arithmetic on the organiser's cut-offs, not a prediction: real races aren't run at an even effort, and every minute stopped comes off the margin.
What if the organiser's file looks wrong?
The analysis checks the file's elevation before trusting it. A stretch of 500 m or more held at exactly one height, or a change of 20 m or more between two points less than 30 m apart, is something the file's author filled in, not the ground. The page says so under the profile, and the totals keep the organiser's figures next to Pendio's.
Who are the "coming from road marathons" notes for?
Courses from 30 to 60 km, where many runners come from the road. The notes put the course in a road runner's terms: how far past a marathon it is, how much of it is steep, how far apart the aid is and where the cut-offs fall. They describe the ground; they aren't advice, and nothing on these pages is medical.