Anything like mixing toilet bowl cleaner and vinegar?
That will kill you!
No, mixing toilet bowl cleaner (it has to be a specific brand, I won’t say which) and aluminum results in very rapid release of gasses, but not toxic ones. The dangerous part is that, if you do this in a container that is closed tightly, the gas has no way to escape except to explode the container. Since the toilet bowl cleaner also contains a solution of acid, that explosion would spray somewhat corrosive chemicals as well.
So, the fact that she knew the right brand of cleaner, used the foil in rolled up balls, and did it in a bottle, then put the cap on, means she was following a specific bomb-making recipe. She literally followed step-by-step the instructions in a bomb-making manual.