Greasy Fork is available in English.
Index competitive duels and display head-to-head statistics on user pages
This script periodically downloads your competitive duels history from your activities list and stores game information in your browser in such a way that it can be queried efficiently. It then uses this data to show you head-to-head statistics (score and elo balance, overall and by game mode, solo or in a team pairing you selected) on each player's user page. In addition, when hovering over the head-to-head score, it displays a list of the most recent games against that player or team (overall or in the respective mode) and links to the respective game summaries. Finally, it adds an interface to the player's own profile page allowing to backup and restore the locally held data.
You've probably played a lot of duels. The script is designed for all downloads to happen in the background while you can continue to use the site as normal. For this reason, it is somewhat conservative in how quickly it sequences duel downloads in order to minimise the probability that you will be rate-limited by Geoguessr, which could impact the functionality of the site as you're using it.
Geoguessr only allows you to query your activity history for the past year. The script is therefore limited to the duels you have played up to one year prior to you installing and running the script for the first time.
The script checks your activity history at most every hour automatically and so the statistics only update once an hour. However, you can trigger an instant check and download via the userscript manager menu (e.g. Tampermonkey) or by clicking the refresh button in the recent games list.
Yes, other userscripts can use the data downloaded by this script to offer more functionality. For instance, you can install the Geoguessr rating graph script to see rating graphs for yourself and your teams on profile pages. Starting from version 0.5.0, round data is also downloaded by this script, which allows you to analyse your performance on a map using the Geoguessr duel round analysis script. If you've been using this script previously to version 0.5.0, you can fill in past round data using the "Fill in round data" button at the bottom of your profile page.