In 2022 I was part of a group of artists, technologists and theorists which made a dataset of xenoimages. This dataset was not functional, but a form of speculative/fictional design, and it was accompanied by a manifesto that we all wrote together. Once written, we decided to dramatise its reading in a presentation event. Your text made me wonder: why do we automatically dramatise reading? Apparently, in our imaginary as artists, that is the only option. You can watch the video of the event here. This is the manifesto in English. And the web which is in Spanish for the moment.
In relation to the theatricality of the manifesto, the dramatised readings of Paul B Preciado's book "Y soy el monstruo que os habla: Informe para una academia de psicoanalistas" [I am the Monster that speaks to you: Report to an Academy of Psychoanalysts]. I do not think he is calling this text "a manifesto", but it could be considered as such: https://www.youtube.com/watch?v=sztXYnuIsrQ&ab_channel=JessG. One more example of the need to bring Manifesto to the theatre space.