XViewer for Pixiv by NEONS

Click an artwork on a pixiv user page and it opens right there in a modal, without leaving the page. Switching between multiple images, playing ugoira, reading the caption, tags, and comments, and even liking, bookmarking, and following all happen inside the modal.
Close it and you are back in the grid, at the same scroll position.
This extension aims for a browsing experience close to viewing media on X (formerly Twitter).

⭐ Key features
・Move between artworks
　Use the up and down keys to move to the previous or next artwork in the grid.
　When you reach the end, the next page is loaded automatically.
　On the Illustrations or Manga tab, it steps through works of that type only.

・Ugoira playback
　Unpacks the zip and assembles the frames, with play and pause support.

・Actual-size view
　Click an image to open it at actual size, filling the screen. (Off by default)

・Sidebar
　Shows the caption, tags, post date, like count, bookmark count, view count, a follow button, and comments.

・Comments
　Post comments and replies without leaving the modal.
　Pick emoji and stickers from a picker.
　You can delete your own comments after a two-step confirmation.

・Infinite scroll
　Turns the pager on illustration and manga lists into continuous loading as you scroll down. (Off by default)
　The page number in the URL follows the page on screen, which is handy for sharing.

⌨ Keyboard shortcuts
Left / Right: Turn pages within the same artwork
Up / Down: Move to the previous or next artwork
Esc: Close the modal

⚙ Settings
Open them from the toolbar icon.
You can turn the viewer on or off and choose the image resolution, how many images to prefetch, whether to show the sidebar and how it scrolls, whether clicking the background closes the viewer, click to view at actual size, Tab movement in the grid, whether to hide the Pickup section, infinite scroll, and the color theme of the settings screen.

🔒 Privacy
This extension sends no data anywhere other than pixiv, and it collects no personal information.
For details, see:
https://xviewer.neonsdesign.com/en/privacy.html

💻 Requirements
Firefox 140 or later (desktop).
For Chromium-based browsers (Chrome, Brave, Edge, etc.), it is available on the Chrome Web Store.

⚠ Notes
・This is an unofficial extension developed using the pixiv platform. It is not an application created or distributed by pixiv Inc., and it has no connection whatsoever with the company. It is not affiliated with, supported by, or endorsed by pixiv Inc.
・Use it at your own risk. Neither the author nor pixiv Inc. is liable for any damage arising from the use of this extension.
・Whether R-18 works are shown follows your pixiv settings. This extension does not bypass age restrictions.
・It may stop working due to changes on pixiv's side.

✉ Bug reports, questions, and requests
The author is a native Japanese speaker from Japan and is not very good at English.
https://forms.gle/C7AWaUHWmwnoeDV66

📄 Source code
This extension is open source.
https://github.com/NEONS-DESIGN/XViewer-for-Pixiv