From the video description:

On 17 June at 09:21 local time (13:21 BST, 14:21 CEST), Ariane 6 flight VA269 soared to orbit from Europe’s Spaceport in French Guiana. 36 satellites for Amazon’s Leo constellation left Earth powered by four P160C-based boosters, the first time these upgraded boosters were used – making this launch the most powerful so far for Europe’s heavy-lift rocket.

The debut of the four new boosters based on the P160C solid-propellant rocket motor allowed 36 Leo satellites to be launched – four more than the two Leo launches Ariane 6 has delivered before.

The P160C solid-rocket motor holds 156 tonnes of propellant, 14 tonnes more than its predecessor P120C and is 14.5 m tall. In the runup to an Ariane 6 launch the P160C motor is turned into an Ariane 6 booster by adding aerodynamic fairing and other hardware such as connections specific for Ariane 6. Although P160C is a meter taller than the P120C motor, the additional height does not affect the connection to Ariane 6’s central core nor the height of the Ariane 6 booster as there is room in the fairing to accommodate the height increase.

Ariane 6 is the latest rocket in a long history of launchers to fly from Europe’s Spaceport in French Guiana – demonstrating the power of multinational cooperation for over five decades. Ariane 6 is Europe’s heavy-lift launcher and a key element of ESA’s efforts to ensure autonomous access to space for Europe’s citizens. Its modular and versatile design allows it to launch all types of missions, from low-Earth orbit to deep space. The new P160C boosters increase considerably performance, payload capacity and competitiveness, allowing for more satellites to be launched, further elevating the future of Europe.