The welding symbols in question are ISO symbols. It appears the welds are deposited from the arrow side and they are complete joint penetration groove welds.

The groove details are incomplete from the welder's perspective. Both the welder and the inspector need to know what the groove angles are, what the root openings are, and the depth of the bevels in order to know what root face is necessary to ensure CJP is achieved.

The term complete joint penetration is the preferred term. Full penetration is not the preferred term.

Best regards - Al

The company I work for does a lot projects that utilize European designs and drawings, and so most of the welding symbols are European (we also do a lot of Canadian drawings, keeps me on my toes for sure!). The symbols you have submitted are for the European welding code (EN) and are definitely for Complete Joint Penetration (CJP) welds. You have two types shown there, one is a single bevel and one is a double bevel, and they are both for a butt-splice type joint configuration, to be welded from the arrow side.
After getting used to working with these symbols myself, I can see some logic in them. The Europeans have done a good job of making the symbol look somewhat like the actual joint will look when put together. I also like the fact that in most cases, they put the desired near side weld on the top side of the symbol, not the bottom. Just remember that they can show it either way, and the dotted line shown represents far side or other side of the arrow.
Good luck!