cl-swank 2:2.20+dfsg-1 (arm64 binary) in ubuntu cosmic

 SLIME is the Superior Lisp Interaction Mode for Emacs.
 .
 SLIME extends Emacs with support for interactive programming in Common Lisp.
 The features are centered around slime-mode, an Emacs minor-mode that
 complements the standard lisp-mode. While lisp-mode supports editing Lisp
 source files, slime-mode adds support for interacting with a running Common
 Lisp process for compilation, debugging, documentation lookup, and so on.
 .
 The slime-mode programming environment follows the example of Emacs’s native
 Emacs Lisp environment. It also includes good ideas from similar systems
 (such as ILISP) and some new ideas.
 .
 SLIME is compatible with the following free Common Lisp implementations:
 CMUCL, SBCL, CCL, CLISP, ECL, ABCL.
 .
 This package contains the Lisp-side server, needed by the Emacs client
 (see package slime).