Blitzer

The Brave and those who take the Risk are ones who survived from their dedication, and you know you're part of that list. And you always will be. Show them who you are.
You can probably beat the game really easily with this perk, as the blast radius is big enough to cover atleast half the Storm Shelter Entrance. Not to mention, one bomb, instant 700 Damage. You can even shoot one of the payloads and create an even larger explosion, and you take out an entire Boss, atleast their unrefined versions. The Elite, I can't say for sure, really.

[Lore]
The Izbucni, formerly just a pipe grenade issued to Blitzer Agents only had the explosives they had in them, which was powerful, but the Blitzers themselves installed designs into the grenades, making them sticky and exploding via a remote detonation.

[Fanmade]
The Blitzer usually specialized in grenades and taking out Enemies both during Raids and to clear the coast whenever they're on a Scavenging Run. However, there was a big flaw : it was automatic, like all the grenades, but it took longer to arm itself, so Scavs had enough time to realize and run away. This was a heavy problem, and Blitzers needed strict timing, strict positions, and knowing the exact positions the grenades were to land in. Realizing the flaws, Blitzers decided to augment their equipment, installing systems to make them sticky and using a remote to detonate them. This was a huge thing for Blitzer Agents, and they could utilize them much better than the original version of the Izbucni.
However, there was another flaw : Rogue Agents started popping up during the Fifth Agent Wave, and a huge number of them were Blitzers who killed their teammates by sticking their grenades onto them, which couldn't be taken off at all unless it was by the Blitzer themself. Those who realized this knew they needed a way to prevent this.
At one point, one Blitzer proposed the idea of having a similar system like how the Flamer Unit 'CHAOS' had nanites inspired by the Lazarus Nanobots. They realized that using this would prevent Friendly Fire incidents and defection of Blitzer Agents.
During the installation of their new nanites, they had discovered ways to create explosives that were more powerful, and cost efficient, as the Izbucni grenades were somewhat expensive at the time. They had realized that the Shrapnel Grenades were actually powerful, mostly because they could disorient Enemies heavily. They then took those grenades and soon found a way on how to install their features into the Izbucni grenades. Not only did the test reveal that they did work, it revealed that they were extremely cost efficient.