+ http://www.backscatterer.org/
+ questionable policy - pay for (quicker) delisting
+ https://support.hornetsecurity.com/hc/en-us/articles/360011880797-Why-are-Hornetsecurity-IP-addresses-listed-at-Backscatterer-
+ as of December 29, 2021: »The removal at the blacklist backscatterer.org can only be done for a fee«
+ https://www.warmy.io/blog/backscatterer-blacklist-how-to-remove-your-ip-from-it
+ in March 17, 2023 does not mention need to pay
+ https://support.forcepoint.com/s/article/Forcepoint-IP-s-blocklisted-by-UCEProtect-and-Backscatterer-org
+ recommend against using it
+ https://whatismyipaddress.com/backscatterer
+ mentions strict delisting process and "express delisting" but nothing further
+ https://bobcares.com/blog/backscatterer-blacklist/
+ goes through the process with screenshots showing express delisting for 109$
+ https://community.cisco.com/t5/email-security/issues-with-www-backscatterer-org-any-one/td-p/1298377
+ more opinions
+ https://www.titanhq.com/blog/warning-ignore-pay-for-de-listing-blacklist-service/
+ Jan 17th, 2020: »UCEProtect also charges a delisting fee. TitanHQ discourages email administrators from using the UCEProtect blacklist and we do not recommend paying for list removal«
+ https://web.archive.org/web/20150320180344/http://www.jvfconsulting.com/blog/130/Backscatterer_Network_Spam_List_Is_Another_UCEPROTECT_Extortion_Scam.html
+ another opinion