They've got the Rohr grenades introduced in 1915, which replaced the old round headed design.
Old.
New.
The rifles are some flavor of Mannlicher, but I'm outside my area of expertise to tell if they are 1888 or 1895, since the picture doesn't show any of the very identifable areas like the muzzle, rear sight, or magazine. The 1895 is more likely based on the time period.
So if you shoot them in the chest they explode? Seems like bad design
Highly unlikely. Military high explosive fillers tend to be difficult to set off incidentally. A bullet strike, even straight through the cast iron body wouldn't set of any of the common fillers. Even a shot hitting the detonator would have to create a spark exactly at the base of detonator so as to start the firing train, but without also destroying it.
I don't know for 100% sure what the filler of Rohr grenades was, since at the moment I can only find a poster that says they are filled with "explosive" (helpful!), but German grenades of the era were filled with TNT, which is one of the stable and common military explosives that is still in use today.
A diagram of the "old style" Rohr grenade:
A modern soldier wearing 40mm explosives on their chest:
They've got the Rohr grenades introduced in 1915, which replaced the old round headed design.
Old.
New.
The rifles are some flavor of Mannlicher, but I'm outside my area of expertise to tell if they are 1888 or 1895, since the picture doesn't show any of the very identifable areas like the muzzle, rear sight, or magazine. The 1895 is more likely based on the time period.