This piece demands the performer sustain the integrity of the counterpoint while executing an 'obligo' that requires the singer to imply the missing part. It is a brilliant display of intellectual rigor in Baroque composition.
Maintaining clear voice-leading amidst the dense contrapuntal texture is the primary pedagogical objective.
Comparable difficulty and character — good candidates for what to learn next.
Capriccio di obligo di cantare la quinta parte senza toccarla is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Capriccio di obligo di cantare la quinta parte senza toccarla lasts about 4 minutes.
Capriccio di obligo di cantare la quinta parte senza toccarla is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Bergamasca by Girolamo Frescobaldi, Capriccio cromatico con ligature al contrario, F 4.08 by Girolamo Frescobaldi, Capriccio di Durezze, F 4.09 by Girolamo Frescobaldi — see the full similar-pieces list on this page.