syncfusion-ebook-links

manifest.json

{
   "manifest_version": 2,
   "name": "Syncfusion e-book links",
   "description": "Replace DOWNLOAD buttons by convenient links",
   "version": "1.0",

   "content_scripts": [ {
      "js": [ "jquery-1.11.1.min.js", "script.js" ],
      "matches": [ "https://www.syncfusion.com/resources/techportal/ebooks" ]
   } ]
}

script.js

function generateMarkDown() {
	var origin = document.location.origin;
	var books = $("#layout22a > div > div > div").map(function() {
		var title = $(this).find("h3 a").text().trim();
		var img = origin + $(this).find("img").attr('src');
		var pdf = origin + $(this).find("a.download:eq(0)").attr("href");
		var mobi = origin + $(this).find("a.download:eq(1)").attr("href");
		return "# " + title + "\n![" +title+"]("+ img +")\n* [Download PDF]("+pdf+")\n* [Download MOBI]("+mobi + ")\n";
	});
	books.sort();
	var md = ""
	for (var i = 0; i < books.length; i++) {
		md += books[i] + "\n";
	};	
	console.log(md);
}

function replaceNextButton() {

	var button = $("p.download-btn input")[0];

	if (button == undefined) {
		console.log("All buttons replaced");
		generateMarkDown();
		return;
	}

	console.log("Replacing " + button.name + "...");

	$.post("https://www.syncfusion.com/resources/techportal/ebooks", 
			"downloadURL=%2Fresources%2Ftechportal%2Febooks%2F"+button.name,
			function(data) { 
				var links = $("a.download", data);				
				if (links.length>0) {
					console.log("Replacing " + button.name + "... OK");
					$(button).replaceWith(links);
				}
				else {
					console.log("Replacing " + button.name + "... Failed");
				}
				replaceNextButton();
			});
}

replaceNextButton();

See the result here:
https://blog.benoitblanchon.fr/syncfusion-ebooks-links/

your wget script not work anymore, it download only a 40KB pdf and 40KB mobi but empty
wget -A pdf,mobi -r -l1 -H -nd https://blog.benoitblanchon.fr/syncfusion-ebooks-links/ -e robots=off