Apache: Hide HTML extension in URLs with htaccess

hide_html.htaccess

# This tag loads the rewrite module
    <IfModule mod_rewrite.c>
# enable the rewrite engine
    RewriteEngine On
# Set your root directory
    RewriteBase /

# Remove the .html extension
    RewriteCond %{THE_REQUEST} ^GET\ (.*)\.html\ HTTP
    RewriteRule (.*)\.html$ $1 [R=301]

# Remove index and reference the directory
    RewriteRule (.*)/index$ $1/ [R=301]

# Remove trailing slash if not a directory
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} /$
    RewriteRule (.*)/ $1 [R=301]

# Forward request to html file, **but don't redirect (bot friendly)**
    RewriteCond %{REQUEST_FILENAME}.html -f
    RewriteCond %{REQUEST_URI} !/$
    RewriteRule (.*) $1\.html [L]
    </IfModule>


# ------------- alternative remove .html version, 2020 -------------------
#remove html file extension https://example.com/page.html 
# to https://example.com/page 
RewriteEngine On 
RewriteCond %{REQUEST_FILENAME} !-d 
RewriteCond %{REQUEST_FILENAME} !-f 
RewriteRule ^([^\.]+)$ $1.html [NC, L] 

The search engine may index these pages as duplicate content, 
to overcome this add a <canonical> meta tag in the HTML file.
Example:
<link rel="canonical" href="https://example.com/blog/first-blog" />