As of Dec.10 2023 I searched for it everywhere and did not find it. So, attached below, you may find an aria2c (version 1.37) static binary compiled (GCC 4.9.2,  GLIBC 2.19-18+deb8u10) on WD MyCloud Gen1 NAS, running clean Debian Jessie (Debian 8) and kernel 3.2.68 armv7l.

Important note: The program was compiled with "--with-ca-bundle='/etc/ssl/certs/ca-certificates.crt". The file must be available and preferably updated.

aria2 version 1.37.0
Copyright (C) 2006, 2019 Tatsuhiro Tsujikawa

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

** Configuration **
Enabled Features: Async DNS, BitTorrent, Firefox3 Cookie, GZip, HTTPS, Message Digest, Metalink, XML-RPC, SFTP
Hash Algorithms: sha-1, sha-224, sha-256, sha-384, sha-512, md5, adler32
Libraries: zlib/1.3 libxml2/2.12.2 sqlite3/3.44.2 OpenSSL/3.2.0 c-ares/1.17.2 libssh2/1.11.0
Compiler: gcc 4.9.2
  built by  armv7l-unknown-linux-gnueabihf
  on        Dec 10 2023 17:48:24
System: Linux 3.2.68 #22 SMP Sat Nov 28 13:38:43 UTC 2015 armv7l

Visit https://aria2.github.io/

Possible alternatives:

• For previous version 1.36 this worked for me: aria2-1.36.0-linux-gnu-arm-rbpi-build1.deb
• For version 1.37 this ought to work but it does not (the program hangs):  arm-linux-musleabi With OpenSSL and zlib-ng