I don't think so. Here is the listing from an epub on my system. the actual content is HTML, some of the metadata is XML.
M Filemode Length Date Time File
- ---------- -------- ----------- -------- ---------------------------------------
-rw-r--r-- 20 5-Feb-2018 23:13:20 mimetype
-rw-r--r-- 240 5-Feb-2018 23:13:20 META-INF/container.xml
-rw-r--r-- 31079 5-Feb-2018 23:13:20 OEBPS/ch10.html
-rw-r--r-- 14395 5-Feb-2018 23:13:20 OEBPS/ch08.html
-rw-r--r-- 148408 5-Feb-2018 23:13:20 OEBPS/UbuntuMono-BoldItalic.otf
-rw-r--r-- 15006 5-Feb-2018 23:13:20 OEBPS/ch02.html
-rw-r--r-- 11985 5-Feb-2018 23:13:20 OEBPS/ch06.html
-rw-r--r-- 11514 5-Feb-2018 23:13:20 OEBPS/content.opf
-rw-r--r-- 335 5-Feb-2018 23:13:20 OEBPS/cover.html
-rw-r--r-- 27481 5-Feb-2018 23:13:20 OEBPS/ch13.html
-rw-r--r-- 13107 5-Feb-2018 23:13:20 OEBPS/ch09.html
-rw-r--r-- 337564 5-Feb-2018 23:13:20 OEBPS/DejaVuSerif.otf
-rw-r--r-- 140008 5-Feb-2018 23:13:20 OEBPS/UbuntuMono-Regular.otf
-rw-r--r-- 15112 5-Feb-2018 23:13:20 OEBPS/ch04.html
-rw-r--r-- 326 5-Feb-2018 23:13:20 OEBPS/toc01.html
-rw-r--r-- 16138 5-Feb-2018 23:13:20 OEBPS/ch03.html
-rw-r--r-- 55286 5-Feb-2018 23:13:20 OEBPS/ch11.html
-rw-r--r-- 12299 5-Feb-2018 23:13:20 OEBPS/ch07.html
-rw-r--r-- 635 5-Feb-2018 23:13:20 OEBPS/titlepage01.html
-rw-r--r-- 14044 5-Feb-2018 23:13:20 OEBPS/epub.css
-rw-r--r-- 4750 5-Feb-2018 23:13:20 OEBPS/preface01.html
-rw-r--r-- 52228 5-Feb-2018 23:13:20 OEBPS/ch12.html
-rw-r--r-- 148888 5-Feb-2018 23:13:20 OEBPS/UbuntuMono-Italic.otf
-rw-r--r-- 10861 5-Feb-2018 23:13:20 OEBPS/ch05.html
-rw-r--r-- 12277 5-Feb-2018 23:13:20 OEBPS/ch01.html
-rw-r--r-- 27907 5-Feb-2018 23:13:20 OEBPS/toc.ncx
-rw-r--r-- 137220 5-Feb-2018 23:13:20 OEBPS/UbuntuMono-Bold.otf
-rw-r--r-- 5754 5-Feb-2018 23:13:20 OEBPS/preface02.html
-rw-r--r-- 1929 5-Feb-2018 23:13:20 OEBPS/copyright-page01.html
-rw-r--r-- 614488 5-Feb-2018 23:13:20 OEBPS/DejaVuSans-Bold.otf
-rw-r--r-- 4427 5-Feb-2018 23:13:20 OEBPS/assets/custom-controls.png
-rw-r--r-- 13377 5-Feb-2018 23:13:20 OEBPS/assets/full-navbar.png
-rw-r--r-- 11254 5-Feb-2018 23:13:20 OEBPS/assets/menu-custom.png
-rw-r--r-- 4560 5-Feb-2018 23:13:20 OEBPS/assets/level-right.png
-rw-r--r-- 14023 5-Feb-2018 23:13:20 OEBPS/assets/postcode.png
-rw-r--r-- 3781 5-Feb-2018 23:13:20 OEBPS/assets/rubik-breadcrumb.png
-rw-r--r-- 26588 5-Feb-2018 23:13:20 OEBPS/assets/navbar-custom.png
-rw-r--r-- 68868 5-Feb-2018 23:13:20 OEBPS/assets/red-background.png
-rw-r--r-- 4200 5-Feb-2018 23:13:20 OEBPS/assets/rubik-pagination.png
-rw-r--r-- 3016 5-Feb-2018 23:13:20 OEBPS/assets/custom-button-outlined.png
-rw-r--r-- 13266 5-Feb-2018 23:13:20 OEBPS/assets/files.png
-rw-r--r-- 51085 5-Feb-2018 23:13:20 OEBPS/assets/table-custom.png
-rw-r--r-- 4820 5-Feb-2018 23:13:20 OEBPS/assets/edit-title.png
-rw-r--r-- 16096 5-Feb-2018 23:13:20 OEBPS/assets/email.png
-rw-r--r-- 6458 5-Feb-2018 23:13:20 OEBPS/assets/pagination.png
-rw-r--r-- 68957 5-Feb-2018 23:13:20 OEBPS/assets/new-customer.png
-rw-r--r-- 3834 5-Feb-2018 23:13:20 OEBPS/assets/cover.png
-rw-r--r-- 476350 5-Feb-2018 23:13:20 OEBPS/assets/BEP_Bulma_final.jpg
-rw-r--r-- 4462 5-Feb-2018 23:13:20 OEBPS/assets/navbar-brand-icon.png
-rw-r--r-- 2682 5-Feb-2018 23:13:20 OEBPS/assets/dropdown-link.png
-rw-r--r-- 2885 5-Feb-2018 23:13:20 OEBPS/assets/title-custom.png
-rw-r--r-- 3786 5-Feb-2018 23:13:20 OEBPS/assets/custom-file.png
-rw-r--r-- 16748 5-Feb-2018 23:13:20 OEBPS/assets/navbar-brand-before.png
-rw-r--r-- 40263 5-Feb-2018 23:13:20 OEBPS/assets/nav.png
-rw-r--r-- 3045 5-Feb-2018 23:13:20 OEBPS/assets/title.png
-rw-r--r-- 18188 5-Feb-2018 23:13:20 OEBPS/assets/popular-book.png
-rw-r--r-- 44985 5-Feb-2018 23:13:20 OEBPS/assets/initial.png
-rw-r--r-- 9215 5-Feb-2018 23:13:20 OEBPS/assets/component-menu.png
-rw-r--r-- 5195 5-Feb-2018 23:13:20 OEBPS/assets/address.png
-rw-r--r-- 7516 5-Feb-2018 23:13:20 OEBPS/assets/heading.png
-rw-r--r-- 28678 5-Feb-2018 23:13:20 OEBPS/assets/metrics.png
-rw-r--r-- 13416 5-Feb-2018 23:13:20 OEBPS/assets/dropdown-content.png
-rw-r--r-- 27274 5-Feb-2018 23:13:20 OEBPS/assets/item.png
-rw-r--r-- 11989 5-Feb-2018 23:13:20 OEBPS/assets/dropdown-desktop.png
-rw-r--r-- 1431 5-Feb-2018 23:13:20 OEBPS/assets/rubik-button.png
-rw-r--r-- 5385 5-Feb-2018 23:13:20 OEBPS/assets/buttons.png
-rw-r--r-- 1138 5-Feb-2018 23:13:20 OEBPS/assets/button.png
-rw-r--r-- 10981 5-Feb-2018 23:13:20 OEBPS/assets/dropdown-hover.png
-rw-r--r-- 32090 5-Feb-2018 23:13:20 OEBPS/assets/loyal-customers.png
-rw-r--r-- 2155 5-Feb-2018 23:13:20 OEBPS/assets/component-select.png
-rw-r--r-- 3544 5-Feb-2018 23:13:20 OEBPS/assets/custom-select.png
-rw-r--r-- 1578947 5-Feb-2018 23:13:20 OEBPS/assets/collections.png
-rw-r--r-- 4727 5-Feb-2018 23:13:20 OEBPS/assets/customers-pagination.png
-rw-r--r-- 13429 5-Feb-2018 23:13:20 OEBPS/assets/media-before.png
-rw-r--r-- 13249 5-Feb-2018 23:13:20 OEBPS/assets/orders-header.png
-rw-r--r-- 5393 5-Feb-2018 23:13:20 OEBPS/assets/price.png
-rw-r--r-- 7041 5-Feb-2018 23:13:20 OEBPS/assets/level-left.png
-rw-r--r-- 1326 5-Feb-2018 23:13:20 OEBPS/assets/checkbox.png
-rw-r--r-- 11060 5-Feb-2018 23:13:20 OEBPS/assets/logo.png
-rw-r--r-- 8426 5-Feb-2018 23:13:20 OEBPS/assets/content-header.png
-rw-r--r-- 22665 5-Feb-2018 23:13:20 OEBPS/assets/table.png
-rw-r--r-- 100708 5-Feb-2018 23:13:20 OEBPS/assets/edit-full.png
-rw-r--r-- 45410 5-Feb-2018 23:13:20 OEBPS/assets/edit-cover.png
-rw-r--r-- 16657 5-Feb-2018 23:13:20 OEBPS/assets/latest-order.png
-rw-r--r-- 163013 5-Feb-2018 23:13:20 OEBPS/assets/grid.png
-rw-r--r-- 16303 5-Feb-2018 23:13:20 OEBPS/assets/loyal-customer.png
-rw-r--r-- 16114 5-Feb-2018 23:13:20 OEBPS/assets/top-menu.png
-rw-r--r-- 2440 5-Feb-2018 23:13:20 OEBPS/assets/email-icon.png
-rw-r--r-- 169969 5-Feb-2018 23:13:20 OEBPS/assets/full.png
-rw-r--r-- 3947 5-Feb-2018 23:13:20 OEBPS/assets/box.png
-rw-r--r-- 10588 5-Feb-2018 23:13:20 OEBPS/assets/menu-rubik.png
-rw-r--r-- 1907 5-Feb-2018 23:13:20 OEBPS/assets/hero.png
-rw-r--r-- 42720 5-Feb-2018 23:13:20 OEBPS/assets/edit-customer.png
-rw-r--r-- 5718 5-Feb-2018 23:13:20 OEBPS/assets/form.png
-rw-r--r-- 4981 5-Feb-2018 23:13:20 OEBPS/assets/edit-price.png
-rw-r--r-- 2552 5-Feb-2018 23:13:20 OEBPS/assets/start.png
-rw-r--r-- 3105 5-Feb-2018 23:13:20 OEBPS/assets/edit-breadcrumb.png
-rw-r--r-- 34428 5-Feb-2018 23:13:20 OEBPS/assets/component-card.png
-rw-r--r-- 22224 5-Feb-2018 23:13:20 OEBPS/assets/info.png
-rw-r--r-- 1818 5-Feb-2018 23:13:20 OEBPS/assets/password.png
-rw-r--r-- 40737 5-Feb-2018 23:13:20 OEBPS/assets/table-bis.png
-rw-r--r-- 11354 5-Feb-2018 23:13:20 OEBPS/assets/media-after.png
-rw-r--r-- 182336 5-Feb-2018 23:13:20 OEBPS/assets/component-body.png
-rw-r--r-- 180982 5-Feb-2018 23:13:20 OEBPS/assets/initial-colors.png
-rw-r--r-- 24948 5-Feb-2018 23:13:20 OEBPS/assets/component-navbar.png
-rw-r--r-- 45064 5-Feb-2018 23:13:20 OEBPS/assets/popular-books.png
-rw-r--r-- 3368 5-Feb-2018 23:13:20 OEBPS/assets/breadcrumb.png
-rw-r--r-- 6493 5-Feb-2018 23:13:20 OEBPS/assets/burger.png
-rw-r--r-- 9235 5-Feb-2018 23:13:20 OEBPS/assets/menu.png
-rw-r--r-- 6387 5-Feb-2018 23:13:20 OEBPS/assets/brand.png
-rw-r--r-- 13198 5-Feb-2018 23:13:20 OEBPS/assets/navbar-start.png
- ---------- -------- ----------- -------- ---------------------------------------
5828262 111 files
but there is no emacs on some platforms, so you cannot access it there. Emacs and emacspeak are great, but I cannot run them on my pone or tablet (and have speech support) (well to be accurate, there are things you can do, but they are complex and error prone and have ppor performance).
I have used epub and mobi based reference books and they are fine provided they are formatted correctly and have the appropriate index. There is nothing about either epub or mobi which would make them any less appropriate than any other format such as html or pdf. Howe easily texinfo can be translated into any of these formats in an acceptable manner is another question. It isn't that it cannot be done, it is a question about whether the existing translaters can handle it appropriately.
sounds like your talking about the ELISP Reference Manual (as opposed to the Emac Manual).
Pretty much everything has a web browser, but it isn't necessary the best interface for some things. I find reading books with a good epub browser is much better than reading a PDF or HTML version in a web browser. More importantly, the user experience is better.