a. Named location: grounds of the Saltworks(Y)
b. Tangible remains: nothing specific I believe, this part of the history is also not mentioned on the Arc-et-Senans official website (N)
c. Major events: smallish internment and POW camps were pretty common all across Europe (N)
d. Timeframe 1939-1945: 1941-1945(Y)

Score 50%, too insignificant?

a. Named location: the Palace (Y)
b. Tangible remains: the room where the Surrender was signed is still there (Y)
c. Major events: I'd say No for being an Italian air force academy and Yes for the "Surrender of Caserta": it was The Day the War Ended in Italy and 1 million German soldiers lay down their arms as the terms of the German unconditional surrender https://www.italystarassociation.org.uk/history/the-day-the-war-ended-in-italy/, it's also in the timeline of WWII events of wikipedia (Y)
d. Timeframe 1939-1945: 1943, 1945 (Y)

Score 100%. It will add a "surrender event" (this one even is captured on film). There were also German surrenders in Berlin and Reims (both outside the WHS areas there).

a. Named location: the KGB building aka 'the corner house' (Y)
b. Tangible remains: was a KGB museum, now for sale, building still in good condition (Y)
c. Major events: example of the June deportation of 1941 ("15,600 men, women, and children, and including 20% of Latvia's last legal government."), also on wiki's timeline of wwii events (Y)
d. Timeframe 1939-1945: 1941 (Y)

Score 100%: to highlight the role of the Soviet Union, mass deportation of tens of thousands of people from the territories occupied in 1940–1941

a. Named location: Palazzo Venezia (Y)
b. Tangible remains: palace is still there (Y)
c. Major events: I'd say minor (creation of the Italian Governorate of Dalmatia), not in wiki's timeline of wwii events (N)
d. Timeframe 1939-1945: Mussolini too early, Treaties of Rome 1941 (Y)

Score 75%: somehow Rome seems not to have been pivotal in Italy's role in WWII, as its actions were more colonial and effectively ended already in 1942.

Connection: Named after Adolf Hitler

City of Luxembourg - The Avenue de la Liberté, a major road leading to the railway station, was renamed "Adolf-Hitlerstraße". (Wikipedia)

Connection: Damaged in World War II

Melaka and George Town - Between 1944 and 1945, Royal Air Force and United States Army Air Force bombers from India repeatedly launched bombing raids on George Town, seeking to destroy naval and administrative facilities. Several colonial buildings were destroyed or damaged, such as the Government Offices, St. Xavier's Institution, Hutchings School (now the Penang State Museum) and the Penang Secretariat Building. (Wikipedia)

Connection: Second World War

Melaka and George Town - George Town fell to the Imperial Japanese Army on 19 December 1941. The Japanese enacted differing policies with each ethnic community. Ethnic Chinese residents arguably suffered the most brutal treatment, as the Imperial Japanese Army massacred thousands of Chinese as part of the Sook Ching campaign to rid anti-Japanese elements in the society. Between 1942 and 1944, George Town became the port of call and a replenishment hub for the submarines of the Japanese, German and Italian Navies. Japanese officials signed the surrender of Penang on board of the HMS Nelson in the port of George Town on 2 September 1945. A British Royal Marines contingent landed at Swettenham Pier on the following day and subsequently dispersed to capture key locations. (Wikipedia)

Connection: Forced labour during WWII

Melaka and George Town - Female residents were also coerced to work as comfort women by the Imperial Japanese Army, with a handful of brothels set up within the city. (Wikipedia) --> Does this also fall under this connection?

Connection: Damaged in World War II

Cracow - Many relics and monuments of national culture in Cracow were looted and destroyed by the Nazis, including the bronze statue of Adam Mickiewicz stolen for scrap. (Wikipedia)

Connection: Damaged in World War I

Wooden Churches of Southern Malopolska - The Saints Philip and James Church in Sękowa was damaged during 1914–1915 years of World War I in the Gorlice–Tarnów Offensive. The wooden material was used for trenches and for firewood. (Wikipedia)

Connection: Destroyed during invasion

Stari Ras and Sopocani - During one of the raids, in 1689, the Ottoman Turks set fire to the monastery and carried off the lead from the church roof. The brotherhood escaped and the monastery remained deserted for over two hundred years, until the 20th century. The church slowly decayed: its vaults caved in, its dome fell down, and the remains of the surrounding buildings were covered with rubble and earth. (Wikipedia)

Connection: Popes

Cracow - Karol Wojtyła was archbishop of Kraków and became Pope John Paul II, the first non-Italian pope in 455 years, in 1978.

Connection: Damaged in World War II

Canterbury - The most devastating raid was on 1 June 1942 during the Baedeker Blitz. On that day alone, 43 people were killed and nearly 100 sustained wounds. Some 800 buildings were destroyed with 1,000 seriously damaged. Although its library was destroyed, the cathedral did not sustain extensive bomb damage and the local Fire Wardens doused any flames on the wooden roof. (Wikipedia)

Tower of London - Although only one bomb fell on the Tower of London in the First World War, the Second World War left a greater mark. On 23 September 1940, during the Blitz, high-explosive bombs damaged the castle, destroying several buildings and narrowly missing the White Tower. After the war, the damage was repaired and the Tower of London was reopened to the public. (Wikipedia)

This falls outside of the "seriously damaged" scope of the connection as the WHS is limited only to the Cathedral, St Augustine's Abbey, and St Martin's Church.

Have added the others.

The buildings of Cracow were not severely damaged, see https://culture.pl/en/article/how-krakow-made-it-unscathed-through-wwii

Damaged in World War II
Yungang Caves
"During the War of Resistance against Japan, some imperialists on the pretext of research hacked off certain images and damaged the caves."

Does this more fall under vandalism and we don't bother with such a connection? Also this quote is from the PRC and the on-site guide also mentioned that the "Japanese stole precious items" but I suppose there isn't any proof of this happening. The caves had been plundered for decades by what could be local bandits/total randos.
https://www.nytimes.com/1979/06/17/archives/chinas-hidden-cave-art-china.html

Connection: Sieges and Battles

Hué - Major losses occurred in 1947 when the Việt Minh seized the Citadel in February. The French led counter-attack laid siege and the six-week ensuing battle destroyed many of the major structures. The core of the city including the Imperial Palace was burned. The Citadel came under fire again on January 31, 1968, as part of the Tet Offensive a Division-sized force of People's Army of Vietnam and Viet Cong soldiers launched a coordinated attack on Huế seizing most of the city. Viet Cong troops occupied some portions of the citadel while South Vietnamese troops occupied others; and allied warplanes targeted the anti-aircraft guns the communists has mounted on the citadel's outer towers. (Wikipedia)

Connection: Prison

Thang Long - In mid-1945 the Citadel was used by the Imperial Japanese Army to imprison over 4000 French colonial soldiers captured during the Japanese coup d'état in French Indochina in March 1945. (Wikipedia)

Connection: Terrorist Attacks

Mahabodhi Temple Complex - On 7 July 2013 a series of ten bombs exploded in and around the Mahabodhi Temple complex. Five people, including two Buddhist monks, were injured by the blasts. The temple itself and the Bodhi Tree were undamaged. However, the Archaeological Survey of India confirmed damage to new structures in the temple complex. The Islamic terrorist group Indian Mujahideen was held responsible for the bombings. (Wikipedia)

It seems more similar to "colonial looting under the pretext of archaeological research" (hello Elgin Marbles), maybe we should create a connection for that. Severe damage in WWII would be a stretch to substantiate.

Right, I suppose that is 10% of the British Museum? That could be a collection alone. "Looted and dispalyed in The British Museum".
Temple of Apollo Epicurius at Bassae: Twenty-three surviving blocks of the frieze from the interior of the temple
Daphni Monastery: Fluted columns, column bases and ionic capitals
Mogao Caves: Dunhuang manuscripts
Rapa Nui: Hoa Hakananai'a (a moai)
Apollo: Elgin Marbles

Masterpieces of Oral and Intangible heritage

The "Masterpieces of Oral and Intangible heritage" program is already supersede by "UNESCO Intangible Cultural Heritage Lists" or ICH, I think we should rename the connection.

Done!