These bars are similar to the “final group” like the ending of many sonatas, symphonies, solos, quartets (normally there are only final chords of quarter or eighth notes). Consider them as a rhythmic fermata. These bars don’t belong to a phrase. It’s up to the composer (or when there is notatet an eye or fermata on the last note it will be up to the interprete or the conductor) how long this last gesture of an ending (“dying”) piece will endure. (Notice the rallentando). Don’t think of formal apects considering these bars, the composer plays with the expections and the attention of the audience, sometimes redundant, sometimes surprising.
So this link says: Hugo Riemann calls this an "enlarged ending"
Stein, 1962: " Phrase is one of the most contradictory terms in music: apart from the fact that it can be used for two-bar as well as eight-bar (or even larger) units, it is often mistakenly used to subdivide several or individual phrases to call."
Misunderstandings can be avoided by recognizing that more than one phrases can be subphrases as a parent phrase (eg, a first [sub- phrase] works as its first half, and a second as its second half ). So musical phrases are something multi-dimensional. The musical dimensions 1.) of the intervention rhythm, 2.) of the functional rhythm (also: 'cadenzrhythmics') and 3.) of the rhythm stages are capable of 'closing' (cadence), ie according to Hugo Riemann 'Endungslängungen' (after one phase to remain unchanged) should mean: to give a final signal.