They say about themselves that they cannot be “tagged” into an ideology because they “follow the will of the people”. Originally, however, they were mostly based on left-wing and green ideas, as witnessed by the fact that they gave resonance to anti TAV/TAP movements (tav is the Lyon-Turin high speed train, tap is the trans-Adriatic pipeline which will convoy Azerbaijan methane in Europe avoiding Ukraine, with all the geopolitical consequences of that). Further, in their absolutely funny way of direct democracy, among the top 10 supported candidates as Republic President (Italy’s head of state), there was Romano Prodi, who is the historical leader of the Italian center/left-wing political alliances.
In addition to what @phelps correctly said about them, it must be added that they (should) found on transparency and the will of morphing Italian politics in a direct democracy rather than a representative democracy. Their guru was famous for his very strange predictions about the use of internet and so on and from these predictions their political instancies come.
in practice, they have supported one of the most right-wing government in Italian history and, as far as concerns their flagship reformations, they acted with rush, as it seems to have become the rule in all Italian political class, sadly