No surprises here. Need to learn shortcuts are marked.
Any GraphViz DOT (*.gv, *.dot) file may be imported (success is reported in JavaScript console log of the browser). Saved file is a standard and rather simple GraphViz DOT file with HTML-like node labels. It is meant to be viewed and printed with GraphViz (open source graph visualization software).
Beware that not all customized browsers allow all shortcuts (do check Ctrl+S (DOT file save) functionality).
vismm is a client-side application. No information is sent or received from network. No information is deliberately stored in browser cache. vismm could be started from its local copy of HTML/CSS/JS file structure. There are examples of CSS/JS to guide creation of custom display styles.
vismm 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 3 of the License, or (at your option) any later version.
vismm 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.
You should have received a copy of the GNU General Public License along with vismm. If not, see <https://www.gnu.org/licenses/>.