Swedrami: Null.
Been using and intend to continue using this peculiar gray matter inside the cranium and a piece of archeo-software called "text editor" to keep track of titles of interest instead.
I could have done that, still can if I want, but mine has an automated aspect, which means I get a history of price changes, and I only need to do one click to get all the prices checked. It beats the hell out of having to manually visit game pages or sales lists.
Of course I have to manually add a game to my wishlist program, which is copy & paste of the game page URL, and so no biggie. I can also set favorites, and just have them checked, which is my usual modus operandi.
On top of that, I have a second wishlist program that is even less effort for me, because it checks the last 100 games added to my GOG Wishlist and thus updates itself. It does not have the same record keeping though, and is indiscriminate in what gets added, as I don't add every wish-listed game to my other program ... it is my fallback though.
I can't remember the last time I actually checked my online Wishlist pages at GOG.