This script does the following:
1) Allows you to export a csv file with your followed series. First you need to explore all of your followed series on https://mangadex.org/follows/manga/0,
once you reach the last page after loading every page you'll have a list of all the series you follow on the site, including the state (reading, complete, dropped, etc). It also keeps track of the last chapter you read of each series and when it was last updated, but that's only possible if you open the series page one by one or if it's on your default follows page already marked as read. The cells are separated by ";"
2) In case a duplicated chapter appears on your follows page it'll be marked with a blue eye instead of the default grey one to indicate that you MOST LIKELY read that chapter already, depending on how groups upload their releases there might be some false positives. And again, to keep track of the last chapter you've read it has to be saved either by detecting it on your Follows page or on the respective series page (the one with /title/). By default the last chapter read is 0 and if that's the case the title will be marked with "❌❌", but if a new chapter is marked as read then that one will be the last recorded. In case a series has a gap between chapters (i.e. last chapter was the 10th and the next update it's an extra way ahead, like 30.5 or something) it'll show that chapters that fill the gap are chapters already read if the chapter that created the gap has been read before by accident. In case you've read a chapter that's ahead of the rest of the available chapters you can mark it as unread and refresh the title page to set a new last read chapter. If there's a gap between chapters like when a group starts releasing new chapters after another group that doesn't upload their on MangaDex you can save that gap to be marked green instead of blue to indicate you can read it. Also, chapters that are most likely extras are marked green too.
3) In case a series skips chapters (i.e. when a sniper group takes over), those chapters will be marked with a red eye instead of the default grey one, and if a group uploads a batch of new chapters, those that aren't the immediate next chapter are marked red too in case of those groups that upload their chapters out of order.
4) There's 2 lists: whitelist and blacklist. There are series with multiple releases per chapter, MangaDex has the option to block groups but sometimes those groups are the only ones that release certain series you like but on other series their releases suck (and there's the "no group" that's a hit or miss), so for those cases there's this option. Whitelist only shows you releases from one particular group for a series (if you want to only read releases from that particular group), while Blacklist blocks releases from one particular group for a series (if you don't that a certain group to be shown for that series but you don't mind seeing the rest of them in case of multiple groups). To add elements to those lists you have to go to the Script Options tab that's on the Follow page, next to Export. The first one is the series id (the number that appears after "title" on the URL) and the second one is the group id (the number that appears after "group" on the URL).
If you only want to download your list you can uncheck the checkbox in the Script Options and then you won't have a multicolor follows page. If you need to contact me you can send me a PM on https://mangadex.org/user/2072/australis