Commentary for Bava Metzia 41:7

These found objects are his: The explanation [of this is] - not specifically these, but rather anything that does not have an identifying mark is surely his. But it needed these to make us understand that they do not have an identifying mark. And for Abbaye, it was needed to make us understand that they were not [cases of] abandonment without awareness. And for Rava, it is possible that it came to make us understand that [this is the law] even though [the owner] did not know that it fell from him, for abandonment without awareness is [still considered] abandonment. And, according to Rava, from that which it teaches - bundles in a public area are his, but in a private area, he announces - it is implied that a knot is an identifying mark...

These found objects are his - These which it goes on to list, are not [meant to be] exclusively these alone, but rather anything that has an identifying mark. But it took these: For Abbaye - who says abandonment without awareness is not [considered] abandonment - to make us understand that even so, they are surely immediately the finder's, [as] since they are significant or weighty, [the owners] will certainly know [about their loss], as it is found in the gemara; and according to Rava, to make us understand - from the extraneous [inclusion] of all these that it goes on to list, or from the implication of one of them - that abandonment without awareness is [still considered] abandonment.

MISHNAH: Which found objects are his, the finders; and which is he not obligated to annonce that he found them, such that the owner of the lost object may come and identify his lost object?

Which found items are his, and which items is he obligated to announce - The explanation of that which it teaches, "Which found items are his"; and it does not teach, "Which found items is he not obligated to announce" is [that it is] to make us understand that even if the other brought witnesses that it fell from him, we do not give it to him. For since it is something that does not have an identifying mark, he presumably surely abandoned it and it became ownerless.