"Rainbow Six Siege" may have an operator that patches instead of breaks walls, game designer Emilien Lomet, interviewed by PC Gamer at a preview event for Operation Neon Dawn, 2018. She said that the "hole-patching" gadget, which was data-mined from Siege's code, is real.

"The idea of having a defender that can plug holes has been in the team for a long time and we've done a lot of prototypes. For a long time, it didn't ring a bell. Some of it was technical, some of it was purely design. The implementation method was not as good as we would have liked. But it is definitely an idea that is super relevant to us, and I'm going to stop talking about it now because otherwise we would be breaking our NDA [non-disclosure agreement]," he said with a laugh.

That reminded me of a post I made on the Siege subreddit in 2017 touting a new operator of my own making (I was very bored with my old job). One of them, "Dell", uses a range cannon that plugs holes with a fast-hardening compound, strongly inspired by the GLOO cannon in 2017's Prey. In my mind, the operator can seal the hole in the wall in the same way that the GLOO Cannon in the gif below seals the fire hazard.

Source CamelWorks on YouTube

With this idea for "Siege" in mind, I asked Romet if he had played "Prey". Actually, I have played "Prey". I'll shut up now. I'll shut up now. I'll shut up now. I'll shut up now!" He said. We left it at that, but Romette's surprised reaction suggested that I was getting close to at least one of the possible directions this gadget could take.

If true, it would be an incredibly unique defensive gadget. For example, in places where wall and hatch defenses are critical to victory, such as a consulate garage or clubhouse armory, an operator who can re-seal a hard-to-break hole would give the defender a second chance to block out a dangerous line of sight. gLOO-style gadgets gadgets would also make perfect rivals for Maverick Maine. Imagine being able to re-block Maverick's sneaky kill hole, or stop him from trying to jump through the bottom of the wall and into the Bandit's battery.

Since Ubi is always developing multiple operators simultaneously, there is no guarantee that the alleged hole plugger will be one of the four new operators in Year 6. Nevertheless, the way Romet talks about the history of the gadget prototypes sounds like the team has arrived at something satisfactory. For all we know, he may be talking about the first operator, scheduled for 2021.