I have just "noticed" a change which has taken place in the title of this site in advance of the preparation of its Nomination for 2021. I presume that this isn't "accidental" and that the intention is to carry it forward through to actual Nomination.
It has been on UK's T List since Jan 2012 as "Slate Industry of North Wales"
But it has been officially identified as being "the UK's next preferred nomination" (these words presumably chosen carefully to show that it will only actually be nominated if it produces an acceptable Nomination in time!!) for "2019" (but really "Jan 2020") under the title of "Slate Landscape of North West Wales"
The replacement of the word "Industry" by "Landscape" seems sensible, but the significance of the change from "North Wales" to "North West Wales" seems to lie in the esoteric workings of the devolved Government of Wales within UK. It has divided Wales into 5 regions for planning and other purposes (South East, South West, Mid (or "Central"), North East and North West). The historic term "North Wales" now has no "official" currency. Various "regional" responsibilities operate at this (new) regional level and it would appear that a determination to demonstrate local powers and pride has dictated the name change!!!
The vast majority of the to-be-nominated sites are indeed within the NW region - but the Southern Gwynedd location is actually within what is now called "Mid Wales"- though would previously have been regarded as being within what would have been called "North Wales"

2021 WHC Nominations: 11

Asia/Pacific (2)
- Jômon Archaeological Sites in Hokkaidô, Northern Tôhoku, and other regions (Japan)
- Gaya Tumuli (Republic of Korea)

Europe (6)
- Frontiers of the Roman Empire - Eastern Danube (Austria, Germany, Hungary, Slovakia)
- Funeral Sites and Memorials of the First World War (Belgium, France)
- ShUM cities of Speyer, Worms and Mainz (Germany)
- Appian Way "Queen viarum" (Italy)
- Talayotic Culture of Minorca (Spain)
- Slate Landscape of North West Wales (United Kingdom)

Latin America (1)
Sítio Roberto Burle Marx (Brazil)

North America (2)
- Tr'ondëk-Klondike (Canada)
- Hopewell Ceremonial Earthworks (USA)

Historic Center of the Port City of Odessa (Ukraine)

http://on.od.ua/2018/12/17/istoricheskij-centr-odessy-nominiruetsya-v-spisok-naslediy a-yunesko-91104/

Turó of the Seu Vella de Lleida (Spain)

https://www.lavanguardia.com/local/lleida/20190109/454051601791/candidatura-seu-vella -lleida-declarar-patrimonio-mundial-unesco-2021.html

Talayotic Culture of Minorca (Spain) also seems to still be aiming for 2021.

https://cadenaser.com/emisora/2019/01/04/radio_menorca/1546609680_349560.html

I note that this article concentrates solely on 1 element of the T List site as defined in Algeria's update of it in 2002 - namely that one called "The Jeddars". The 2002 update created a T List site consisting of 6 locations including the "Jeddars" whose place on Algeria's T List went back to 1985.

It will be interesting to see if this reflects a specific decision by Algeria to concentrate on that location alone or whether the press report just happened to do so. I admit to a personal "interest" in that decision, having visited (and reviewed) 2 of the OTHER locations!!!!