All airlines I have flown with so far specify both the dimensions and the weight for their carry-on allowance. Most also allow a "personal item" (or under-the-seat luggage) and when they do, they specify maximum dimensions, but NOT the maximum weight for this item (as far as I can tell).
In particular ITA Airways (who I will be flying with next week) have this to say on the topic of hand baggage (emphasis mine):
The hand baggage you bring on board with you may weigh no more than 8 kg and measure no more than 55 cm in height, 35 cm in width and 25 cm in depth including handles, side pockets and wheels.
ITA SpA also lets you bring an accessory of your choice from the following:
- Handbag
- Work backpack
- Laptop computer
[...]
The groundcrew will provide an “Under the seat” label for all small luggage (no larger than 36 cm in height, 45 cm in width and 20 cm in depth) for all domestic and international ITA SpA flights for all destinations.
The first highlight in the first paragraph might suggest that 8kg is the total weight passengers are allowed to bring along in luggage. Considering that the second highlighted passage is added onto this information with an "and", that reading doesn't make sense to me. Even more so since they go on to say that one can "also" bring luggage of another description. This "other" luggage seems to be what's referred to in the last paragraph which specifies only outer dimensions.
Is there usually a restriction to the weight of this personal item on European flights (and in particular on ITA flights)? If so, where can I usually find this information?