What is an observational signature?
Even when there is no known H/T predicting the presence of a phenomenon, said phenomenon can still be falsifiable by observational signature. That if such a phenomenon exist, those and those observations and experiment results will follow. Failure to detect them in cases where they would be detected if the phenomenon existed, thus falsifies the phenomenon. If such a falsifiable phenomenon passes many tests without falsification, that may falsify H/Ts predicting that the phenomenon should not exist.
Examples of observation signatures
Historic examples of observation signature science
One example from the history of science is that the planets orbiting the Sun in elliptical orbits, as suggested by Kepler, made falsifiable predictions that passed many tests before Newtonian mechanics predicted such orbits on theoretical grounds.
Modern and future examples of observation signaturing
If, for example, calculations show what observable effects a distortion of space that does not distort time would produce, that is a falsifiable phenomenon. If many observations confirm said falsifiable predictions in a certain place, or many experiments show those falsifiable predictions repeating under certain conditions, it is a supported falsifiable phenomenon.
Adding the articles to categories
On Falsifiable Scientific Method Media Wiki, falsifiable phenomena can be added as articles in a similar manner as H/Ts, but in a separate category (Observational signatures). The category is called Observsigns.
Articles in the category of observational signatures are to begin with Observsign: . Not Observsing: but Observsign: .